Open Access
Open Peer Review

This article has Open Peer Review reports available.

How does Open Peer Review work?

The survival and the long-term trends of patients with gastric cancer in Shanghai, China

BMC Cancer201414:300

DOI: 10.1186/1471-2407-14-300

Received: 4 January 2013

Accepted: 23 April 2014

Published: 29 April 2014

Abstract

Background

Gastric cancer remains a major health issue and a leading cause of death worldwide. This study presented a long-term survival data of gastric cancer registered in Shanghai of China from 1972–2003, with aims to describe the trends as well as the age, sex, stage and tumor sites specific characteristics.

Methods

The main source of information on cancer cases was the notification card sending to the registry. The residential status of cancer cases was confirmed by home-visits. The methods of follow-up have been a mixture of both active and passive ones.

Results

We observed an increased trend of survival probability during the last decades. Patients diagnosed during 1972–1976 had a 5-years relative survival rate at 12% for males and 11% for females, respectively, which had dramatically increased to 30% for male and 32% for female patients respectively during the period of 2002–2003. Among the patients diagnosed in 2002–2003, the overall survival probability declined with patient’s age at the time of diagnosis. The lowest survival rate was observed among the oldest group, with the median survival time of 0.8 years. Patients diagnosed with stage I had a higher relative survival rate. Patients with cardia cancer had the worst prognosis, with the 5-year relative survival rate of 29%.

Conclusions

The survival probability of patients with gastric cancer in Shanghai has improved significantly during the last decades. Age, stage and site of tumor have an impact on prognosis.

Background

Gastric cancer is one of the most common cancers worldwide, accounting for about 8% of all new cancer cases [1]. In recent decades, the morbidity and mortality of gastric cancer have fallen down dramatically, with the decline first taking place in the countries with low incidence while the decline in the regions with high incidence was relatively slow [24]. Compared with the steady decrease in the United States and European countries, the incidence of gastric cancer remains high in the Far East areas, where up to 100 cases per 100000 populations are reported annually [4]. Despite an overall decrease of incident gastric cancer has been observed in China, the decline was less dramatic than other countries and even there was an increase in the youngest and oldest groups [5].

In recent years, prognosis of patients with gastric cancer has improved significantly [6]. Like other health indices, information on survival statistics is an important component in monitoring cancer control activities, which may suggest possible reasons for the variations and provide targets for the improvement towards them. Based on the registry database of gastric cancer in Shanghai of China since 1970s, we performed the current descriptive study. The aim of this study is to present the survival data and to illuminate relevant trends as well as the age, sex, stage of disease and tumor sites specific characteristics.

Methods

Shanghai is situated on the bank of the Yangtz River Delta of Eastern China, which is the largest city in China and the eighth largest city in the world, with a population of 14.0 million (2010 year-end registered population). It includes urban and suburb areas, where the urban covers 9 districts locating in the center of the municipality, and the suburb covers the other 9 districts. The data of gastric cancer for this study were derived from the Shanghai Cancer Registry Center (SCRC), compiled by the Shanghai Center for Disease Control and Prevention (CDC). The SCRC was established in the 1960s, which has been contributing data to the quinquennial IARC publication Cancer Incidence in Five Continents since Vol. IV [7]. The main source of information on cancer cases was the notification card consisting of basic information for cancer registration that was sent to the SCRC. The residential status of cancer cases was confirmed by home-visits [7]. We obtained the follow-up data of gastric cancer patients diagnosed in 2002–2003 for survival trend analysis, as well as previous published survival data of the other four periods (1972–1976, 1980–1984, 1988–1991, and 1992–1995) which were referred to the “Cancer incidence, mortality and survival rates in urban Shanghai (1973–2000)” [8] and “Cancer survival in Shanghai, China (1992–1995) [9]. We identified the gastric cancer cases using the 10th Revision of the International Classification of Diseases (code C16) [10]. The cancer registry has been using AJCC/UICC TNM staging system in combination with the clinical stages classification system (I-IV).

Patients reported to SCRC were followed up for confirmed diagnosis and survival. The methods of follow-up have been a mixture of both active and passive ones. With passive follow-up, information on death is routinely obtained from the death certificates in the vital statistical section of Shanghai CDC. Through this approach, patients whose death information has not been received may be considered to be “alive” until that point of time. Furthermore, the mortality data are periodically matched with the incident database of cancers. The vital status of the unmatched incident cases is then verified by home visits or postal/telephone enquiries. Active follow-up is necessary in the absence of reliable health information. Reports of deaths from hospitals, living status from the community, or loss to follow-up were updated until December 31, 2010. The censor was defined as still alive at the closing date, or lost to follow-up or died by other causes other than gastric cancer. The survival probability was estimated using random censoring data. In the study, a total of 61140 gastric cancer cases were included for the above-mentioned five periods (Additional file 1: Table S1), among which 10909 cases were registered during the period of 2002 to 2003. The study was approved by the Ethical Review Committee at Shanghai Municipal CDC [11].

Both observed and relative survival probabilities were estimated. Life tables were constructed to calculate the cumulative probability of survival at time ti+1 from the conditional probabilities of survival during consecutive intervals of follow-up time up to and including ti+1. Relative survival is a measure of net survival calculated by comparing observed survival with expected survival from a comparable set of people that do not have cancer. It is used to measure the excess mortality that is associated with a cancer diagnosis, and is designed to exclude the effect arising from different background mortalities. The relative survival (Ri) for a group of patients at the end of an interval beginning at time ti was defined as R i = S i S i * , where Si was the absolute survival for subjects with a gastric cancer and Si * was the expected survival of a group of individuals with the same demographic characteristics (age, and sex, etc.) who were at risk of death only from causes other than the cancer under study. Chi-Square test was used to compare the distribution between males and females. Furthermore, Log rank test was used to compare the survival rates with 95% confidence interval (CI). Written informed consent was obtained from the patient for the publication of this report and any accompanying images.

Results

As showed in Table 1, there were 10909 newly diagnosed gastric cancer cases reported during 2002–2003, including 47.1% living in the urban and 52.9% living in the suburb. Among them, there were 7038 (64.5%) males and 3871 (35.5%) females. Patients aged 65–84 years accounted for more than 58% of all cases.The proportion of patients being classified as stage I to IV was 5.5%, 9.9%, 12.4%, and 13.8% respectively, while 58.4% of cases were reported with “unknown stage”. The gender difference of tumor sites was significant (χ2 = 79.41, P < 0.001). Malignant neoplasm of pyloric antrum account for 22.3% and 4796 (44.0%) cases were reported with unspecified sites. At the time of the last follow-up (December 31, 2010), 8365 (76.7%) patients died, 2312 (21.2%) patients were alive, and 232 (2.1%) cases were lost to follow up.
Table 1

General information of patients with gastric cancer during 2002–2003 in Shanghai, China

Variables

 

Total

Male

Female

χ2#

P

Area

      
 

Urban

5139 (47.1)

3270 (46.5)

1869 (48.3)

3.32

0.068

 

Suburb

5770 (52.9)

3768 (53.5)

2002 (51.7)

  

Age-group

      
 

15-

107 (1.0)

45 (0.6)

62 (1.6)

125.18

<0.001

 

35-

541 (5.0)

292 (4.1)

249 (6.4)

  
 

45-

1625 (14.9)

1032 (14.7)

593 (15.3)

  
 

55-

1720 (15.8)

1220 (17.3)

500 (12.9)

  
 

65-

3545 (32.5)

2367 (33.6)

1178 (30.4)

  
 

75-

2881 (26.4)

1828 (26.0)

1053 (27.2)

  
 

85+

490 (4.5)

254 (3.6)

236 (6.1)

  

Tumor site*

      
 

C16.0

1371 (12.6)

1005 (14.3)

366 (9.5)

79.41

<0.001

 

C16.1

171 (1.6)

119 (1.7)

52 (1.3)

  
 

C16.2

873 (8.0)

536 (7.6)

337 (8.7)

  
 

C16.3

2436 (22.3)

1545 (22.0)

891 (23)

  
 

C16.4

106 (1.0)

67 (1.0)

39 (1.0)

  
 

C16.5

758 (6.9)

527 (7.5)

231 (6)

  
 

C16.6

62 (0.6)

30 (0.4)

32 (0.8)

  
 

C16.8

336 (3.1)

222 (3.2)

114 (2.9)

  
 

C16.9

4796 (44.0)

2987 (42.4)

1809 (46.7)

  

Stage

      
 

I

601 (5.5)

394 (5.6)

207 (5.3)

8.371

0.079

 

II

1085 (9.9)

721 (10.2)

364 (9.4)

  
 

III

1353 (12.4)

902 (12.8)

451 (11.7)

  
 

IV

1504 (13.8)

982 (14.0)

522 (13.5)

  
 

Unknown

6366 (58.4)

4039 (57.4)

2327 (60.1)

  

Vital status

      
 

Died

8365 (76.7)

5454 (77.5)

2911 (75.2)

7.96

0.019

 

Survival

2312 (21.2)

1445 (20.5)

867 (22.4)

  
 

Lost to follow up

232 (2.1)

139 (2.0)

93 (2.4)

  

*C16.0, Malignant neoplasm of cardia; C16.1, Malignant neoplasm of fundus of stomach; C16.2, Malignant neoplasm of body of stomach; C16.3, Malignant neoplasm of pyloric antrum; C16.4, Malignant neoplasm of pylorus; C16.5, Malignant neoplasm of lesser curvature of stomach, unspecified; C16.6, Malignant neoplasm of greater curvature of stomach, unspecified; C16.8, Malignant neoplasm of overlapping sites of stomach; C16.9, Malignant neoplasm of stomach, unspecified.

#Chi-Square test was used to compare the distribution between males and females.

Overall survival rate

Among gastric cancer patients diagnosed during the period 2002–2003 in Shanghai, the 1-year observed survival rate was 51% for male and 52% for female, respectively. The 5-years observed survival rate decreased to 25% for male and 27% for female, respectively. The 1-year relative survival rate was 54% for male and 56% for female patients, respectively. The 5-years relative survival rate was 30% for male and 32% for female patients, respectively. The median survival time was 1.09 years. Patients living in the urban had slightly higher survival rate compared with the patients in the suburb (Table 2).
Table 2

Survival rate of patients with gastric cancer in different regions during 2002–2003 in Shanghai, China

Area

Sex

N

Observed survival rate [% (95% CI)]

Relative survival rate [% (95% CI)]

Median survival (years)

1 year

2 years

3 years

4 years

5 years

1 year

2 years

3 years

4 years

5 years

 

Total

10909

51 (50–52)

37 (36–38)

31 (30–32)

28 (27–29)

26 (25–27)

55 (54–56)

41 (40–42)

35 (34–36)

32 (31–33)

30 (29–31)

1.09

Whole city

Male

7038

51 (50–52)

37 (36–38)

30 (29–31)

27 (26–28)

25 (24–26)

54 (53–55)

40 (39–41)

34 (33–35)

31 (30–32)

30 (29–31)

1.06

 

Female

3871

52 (50–54)

38 (36–40)

32 (31–34)

30 (29–31)

27 (26–28)

56 (54–58)

42 (40–44)

37 (36–39)

34 (33–36)

32 (31–34)

1.14

 

χ2*

 

1.05

2.14

6.29

10.09

6.42

-

-

-

-

-

 
 

P*

 

0.305

0.144

0.012

0.001

0.011

-

-

-

-

-

 

Urban

Total

5139

52 (51–53)

38 (37–39)

32 (31–33)

28 (27–29)

26 (25–27)

56 (55–57)

42 (41–43)

36 (35–37)

33 (32–34)

31 (30–32)

1.13

 

Male

3270

51 (49–53)

37 (35–39)

30 (28–32)

27 (25–29)

25 (24–27)

55 (53–57)

41 (39–43)

35 (33–37)

32 (30–34)

31 (29–33)

1.07

 

Female

1869

53 (51–55)

40 (38–42)

34 (32–36)

31 (29–33)

28 (26–30)

58 (56–60)

45 (43–47)

39 (37–41)

36 (34–38)

33 (31–35)

1.24

 

χ2*

 

2.02

6.67

6.29

8.65

3.77

-

-

-

-

-

 
 

P

 

0.155

0.010

0.012

0.003

0.052

-

-

-

-

-

 

Suburb

Total

5770

51 (50–52)

36 (35–37)

30 (29–31)

27 (26–28)

26 (25–27)

54 (53–55)

39 (38–40)

33 (32–34)

31 (30–32)

30 (29–31)

1.05

 

Male

3768

51 (49–53)

37 (35–39)

30 (29–32)

27 (26–28)

25 (24–26)

54 (52–56)

40 (38–42)

33 (32–35)

31 (30–33)

29 (28–31)

1.05

 

Female

2002

51 (49–53)

36 (34–38)

31 (29–33)

29 (27–31)

27 (25–29)

55 (53–57)

39 (37–41)

35 (33–37)

33 (31–35)

31 (29–33)

1.05

 

χ2*

 

0.01

0.21

1.11

2.48

2.70

-

-

-

-

-

 
 

P*

 

0.954

0.645

0.292

0.115

0.100

-

-

-

-

-

 

*Log rank test was used to compare the survival rates between males and females.

Age-specific survival rate

Table 3 showed the survival rate of gastric cancer at different ages. We excluded the cases younger than 35 years or older than 85 years for survival analysis because of insufficient number of cases at these age groups. In general, the overall survival probability declined with the increase of patient’s age at the time of diagnosis. The lowest survival rate was observed among the oldest group (75–84 years), with the median survival time of 0.8 years. The age related trend of survival rate was different between male and female patients. For male patients, the youngest group (35–44 years) had the highest survival rate with the longest median survival time of 2.3 years. However, the survival probability at 35–44 years age group was worse than those aged 45–64 years among female gastric patients (Table 3).
Table 3

Survival rate of patients with gastric cancer at different ages during 2002–2003 in Shanghai, China

Age (years)

Sex

N

Observed survival rate [% (95% CI)]

Relative survival rate [% (95% CI)]

Median survival (years)

1 year

2 years

3 years

4 years

5 years

1 year

2 years

3 years

4 years

5 years

35-44

Male

292

66 (60–71)

52 (46–58)

46 (40–52)

44 (38–50)

43 (37–49)

66 (60–72)

52 (46–58)

47 (41–53)

45 (39–51)

44 (38–50)

2.3

Female

249

62 (56–68)

51 (45–57)

43 (37–49)

40 (34–46)

39 (33–45)

62 (56–68)

51 (45–57)

44 (38–51)

40 (34–47)

40 (34–47)

2.1

45-54

Male

1032

66 (63–69)

52 (49–55)

45 (42–48)

42 (39–45)

41 (38–44)

66 (63–69)

52 (49–55)

46 (43–49)

44 (41–47)

43 (40–46)

2.3

Female

593

67 (63–71)

54 (50–58)

48 (44–52)

45 (41–49)

43 (39–47)

67 (63–71)

54 (50–58)

49 (45–53)

46 (42–50)

44 (40–48)

2.7

55-64

Male

1220

59 (56–62)

45 (42–48)

38 (35–41)

35 (32–38)

33 (30–36)

60 (57–63)

46 (43–49)

40 (37–43)

38 (35–41)

37 (34–40)

1.7

Female

500

61 (57–65)

48 (44–52)

42 (38–46)

41 (37–45)

38 (34–42)

61 (57–65)

48 (44–53)

44 (40–49)

42 (38–47)

41 (37–46)

1.8

65-74

Male

2367

52 (50–54)

37 (35–39)

30 (28–32)

26 (24–28)

24 (22–26)

54 (52–56)

40 (38–42)

34 (32–36)

33 (31–35)

35 (33–37)

1.1

Female

1178

56 (53–59)

41 (38–44)

34 (31–37)

31 (28–34)

28 (25–31)

56 (53–59)

43 (40–46)

37 (34–40)

36 (33–39)

35 (32–38)

1.4

75-84

Male

1828

37 (35–39)

23 (21–25)

17 (15–19)

14 (12–16)

12 (11–14)

40 (38–42)

29 (27–31)

26 (24–28)

28 (26–30)

34 (32–36)

0.8

Female

1053

38 (35–41)

23 (21–26)

17 (15–19)

15 (13–17)

13 (11–15)

40 (37–43)

26 (23–29)

23 (21–26)

25 (22–28)

27 (24–30)

0.8

Stage of disease and survival rate

Patients were classified into different clinical stages (I-IV) according to AJCC /UICC TNM staging system, where the lower stage indicated the early clinical phase of the disease. Based on the survival data from SCRC, it was obvious that patients diagnosed with lower stages had significantly better prognosis. The 5-years relative survival rate was over 80% among patients at the stage I. However, it dramatically decreased to 10% when patients were diagnosed at stage IV. The 5-years relative survival rate of males is slightly higher than that of females except for those diagnosed at stage IV(Table 4).
Table 4

Survival rate of patients with gastric cancer in different stages during 2002–2003 in Shanghai, China

Stage

Sex

N

Observed survival rate [% (95% CI)]

Relative survival rate [% (95% CI)]

Median survival (years)

1 year

2 years

3 years

4 years

5 years

1 year

2 years

3 years

4 years

5 years

I

Male

394

88 (84–91)

80 (76–84)

73 (68–77)

69 (64–73)

68 (63–73)

91 (88–94)

85 (81–88)

83 (79–87)

84 (80–88)

88 (85–91)

>5

Female

207

90 (85–94)

80 (74–85)

74 (67–80)

71 (64–77)

67 (60–73)

93 (89–96)

85 (79–90)

81 (75–86)

82 (76–87)

81 (75–86)

>5

II

Male

721

79 (76–82)

64 (60–67)

55 (51–59)

51 (47–55)

48 (44–52)

81 (78–84)

69 (65–72)

63 (59–67)

63 (59–67)

64 (60–68)

4.38

Female

364

78 (73–82)

66 (61–71)

58 (53–63)

53 (48–58)

50 (45–55)

81 (77–85)

70 (65–75)

64 (59–69)

61 (56–66)

61 (56–66)

4.91

III

Male

902

59 (56–62)

41 (38–44)

31 (28–34)

27 (24–30)

25 (22–28)

62 (59–65)

45 (42–48)

36 (33–39)

34 (31–37)

35 (32–38)

1.51

Female

451

62 (57–66)

42 (37–47)

35 (31–40)

31 (27–36)

29 (25–33)

64 (60–69)

44 (39–49)

39 (35–44)

36 (32–41)

36 (32–41)

1.58

IV

Male

982

27 (24–30)

15 (13–17)

11 (9–13)

8 (6–10)

7 (6–9)

29 (26–32)

17 (15–20)

13 (11–15)

11 (9–13)

10 (8–12)

0.68

Female

522

28 (24–32)

15 (12–18)

11 (9–14)

9 (7–12)

8 (6–11)

29 (25–33)

17 (14–21)

13 (10–16)

11 (8–14)

10 (8–13)

0.69

Unknown

Male

4039

46 (44–48)

32 (31–33)

26 (25–27)

23 (22–24)

21 (20–22)

50 (49–52)

37 (36–39)

33 (32–35)

33 (32–35)

34 (33–36)

0.93

Female

2327

48 (46–50)

34 (32–36)

29 (27–31)

27 (25–29)

24 (22–26)

54 (52–56)

40 (38–42)

36 (34–38)

36 (34–38)

36 (34–38)

0.96

Tumor sites and survival rate

Survival rate of gastric cancer varied among different tumor sites. The worst prognosis was observed in patients with cardia cancer, as the 5-years relative survival rate was only 29% (Table 5).
Table 5

Survival rate of patients with gastric cancer in different tumor sites during 2002–2003 in Shanghai, China

Tumor sites

Sex

N

Observed survival rate [% (95% CI)]

Relative survival rate [% (95% CI)]

Median survival (years)

1 year

2 years

3 years

4 years

5 years

1 year

2 years

3 years

4 years

5 years

C16.0 Cardia

Male

1005

49 (46–52)

33 (30–36)

24 (21–27)

20 (18–23)

18 (16–21)

52 (49–55)

37 (34–40)

30 (27–33)

28 (25–31)

29 (26–32)

1.0

 

Female

366

53 (48–58)

34 (29–39)

26 (22–31)

23 (19–28)

21 (17–26)

57 (52–62)

39 (34–44)

32 (27–37)

30 (25–35)

29 (24–34)

1.1

C16.1 Fundus

Male

119

53 (44–62)

43 (34–52)

38 (29–47)

31 (23–40)

29 (21–38)

55 (45–64)

47 (38–56)

44 (35–53)

40 (31–50)

41 (32–51)

1.3

 

Female

52

67 (52–79)

53 (39–67)

47 (33–61)

45 (31–59)

43 (30–57)

70 (55–81)

58 (43–71)

54 (40–68)

55 (41–70)

57 (43–71)

2.5

C16.2 Body

Male

536

55 (51–59)

39 (35–43)

32 (28–36)

29 (25–33)

27 (23–31)

57 (53–61)

43 (39–47)

37 (33–41)

37 (33–41)

38 (34–42)

1.3

 

Female

337

58 (53–63)

45 (40–50)

38 (33–43)

34 (29–39)

31 (26–36)

60 (55–65)

47 (42–52)

41 (36–46)

39 (34–44)

37 (32–43)

1.6

C16.3 Pyloric antrum

Male

1545

60 (58–62)

44 (42–47)

37 (35–39)

33 (31–35)

31 (29–33)

64 (62–66)

50 (48–53)

45 (42–48)

44 (42–47)

45 (43–48)

1.6

 

Female

891

59 (56–62)

46 (43–49)

39 (36–42)

37 (34–40)

34 (31–37)

63 (60–66)

51 (48–54)

45 (42–48)

45 (42–48)

45 (42–48)

1.7

C16.4 Pylorus

Male

67

71 (58–81)

55 (42–67)

49 (37–61)

44 (32–57)

41 (29–54)

77 (66–87)

62 (50–74)

59 (47–72)

58 (46–70)

59 (47–72)

2.8

 

Female

39

69 (52–82)

59 (42–74)

54 (38–70)

49 (33–65)

46 (30–62)

73 (55–85)

64 (47–79)

62 (45–77)

60 (42–74)

62 (45–77)

3.7

C16.5 Lesser curvature

Male

527

74 (70–78)

60 (56–64)

53 (49–57)

50 (46–54)

47 (43–51)

76 (72–80)

64 (60–68)

60 (56–64)

60 (56–64)

61 (57–65)

3.9

 

Female

231

72 (66–78)

57 (50–63)

54 (47–61)

50 (43–57)

46 (39–53)

75 (69–80)

61 (54–67)

59 (52–65)

57 (51–64)

57 (51–64)

3.9

C16.6 Greater curvature

Male

30

77 (58–90)

53 (34–71)

40 (23–59)

40 (23–59)

40 (23–59)

81 (61–92)

59 (41–77)

47 (28–66)

51 (31–69)

55 (37–75)

2.2

 

Female

32

71 (52–85)

52 (34–70)

48 (30–66)

48 (30–66)

48 (30–66)

78 (60–91)

58 (41–76)

57 (38–74)

60 (41–76)

65 (47–81)

2.4

C16.8 Overlapping sites

Male

222

48 (41–55)

29 (23–36)

24 (19–30)

21 (16–27)

20 (15–26)

50 (43–57)

33 (27–40)

29 (23–35)

28 (22–34)

30 (24–37)

1.0

 

Female

114

61 (51–70)

44 (35–54)

37 (28–47)

34 (26–44)

32 (24–41)

63 (54–72)

47 (38–57)

42 (33–52)

41 (32–51)

40 (31–50)

1.6

C16.9 Unspecified

Male

2987

42 (40–44)

29 (27–31)

24 (22–26)

21 (20–23)

20 (19–21)

45 (43–47)

34 (32–36)

30 (28–32)

30 (28–32)

31 (29–33)

0.9

 

Female

1809

43 (41–45)

30 28–32)

25 (23–27)

23 (21–25)

21 (19–23)

48 (46–50)

35 (33–37)

31 (29–33)

31 (29–33)

31 (29–33)

0.9

Stratification analysis by age and stage

In each age group, the 5-years survival rate declined with the increase of tumor stages. For patients at stage I and II, the 5-year survival rates were higher among those aged 35–44 years (81% and 69%, respectively). For patients at stage III–IV, the 5-year survival rates were higher among those aged 45–54 years (36% and 14%, respectively) (Table 6).
Table 6

Survival rate of patients with gastric cancer stratified by age and stage during 2002–2003 in Shanghai, China

Age (years)

Stage*

N

Observed survival rate [% (95% CI)]

1 year

2 years

3 years

4 years

5 years

35-44

I

44

95 (83–99)

88 (74–95)

86 (72–94)

81 (66–91)

81 (66–91)

 

II

77

89 (79–95)

76 (65–85)

72 (60–81)

69 (57–79)

69 (57–79)

 

III

80

71 (60–80)

51 (40–62)

41 (30–53)

36 (26–48)

32 (22–43)

 

IV

95

22 (14–32)

12 (7–21)

5 (2–12)

4 (1–11)

3 (1–9)

45-54

I

127

98 (93–100)

93 (87–97)

87 (80–92)

83 (75–89)

82 (74–88)

 

II

221

89 (84–93)

74 (68–80)

68 (61–74)

61 (54–67)

59 (52–65)

 

III

244

74 (68–79)

52 (46–58)

43 (37–49)

39 (33–45)

36 (30–42)

 

IV

264

33 (27–39)

20 (15–25)

18 (14–23)

15 (11–20)

14 (10–19)

55-64

I

126

90 (83–94)

86 (78–91)

82 (74–88)

80 (72–86)

78 (70–85)

 

II

225

80 (74–85)

70 (63–76)

62 (55–68)

59 (52–65)

56 (49–63)

 

III

243

60 (54–66)

40 (34–46)

32 (26–38)

27 (22–33)

26 (21–32)

 

IV

242

35 (29–41)

17 (13–22)

12 (8–17)

9 (6–14)

9 (6–14)

65-74

I

207

87 (81–91)

76 (69–82)

69 (62–75)

67 (60–73)

64 (57–70)

 

II

354

75 (70–79)

61 (56–66)

52 (47–57)

49 (44–54)

45 (40–50)

 

III

469

61 (56–65)

43 (38–48)

32 (28–36)

29 (25–33)

27 (23–31)

 

IV

492

29 (25–33)

16 (13–20)

11 (8–14)

9 (7–12)

7 (5–10)

75-84

I

82

77 (66–85)

57 (46–68)

45 (34–56)

37 (27–48)

31 (22–42)

 

II

175

70 (63–77)

50 (42–58)

36 (29–44)

31 (24–39)

26 (20–33)

 

III

276

46 (40–52)

26 (21–32)

21 (16–26)

18 (14–23)

17 (13–22)

 

IV

345

21 (17–26)

12 (9–16)

9 (6–13)

6 (4–9)

5 (3–8)

*Cases with unknown stages were not involved in the analysis.

Long-term trends of survival rate

The trends of long-term survival data were available for patients spanning in the four time periods (1972–1976, 1980–1984, 1988–1991, and 2002–2003). An obvious increased trend of survival probability could be found during the last decades in either male or female patients (Figures 1 and 2). For example, gastric cancer patients diagnosed during 1972–1976 had a 5-years relative survival rate at 12% for males and 11% for females, respectively, which dramatically increased to 30% for male and 32% for female patients respectively during the period of 2002–2003 (Table 7).
https://static-content.springer.com/image/art%3A10.1186%2F1471-2407-14-300/MediaObjects/12885_2013_Article_5242_Fig1_HTML.jpg
Figure 1

Observed and relative survival rate of male gastric cancer patients.

https://static-content.springer.com/image/art%3A10.1186%2F1471-2407-14-300/MediaObjects/12885_2013_Article_5242_Fig2_HTML.jpg
Figure 2

Observed and relative survival rate of female gastric cancer patients.

Table 7

Comparison of survival rate of patients with gastric cancer from 1972 to 2003 in Shanghai, China

Sex

Year

N

Observed survival rate [% (95% CI)]

Relative survival rate [% (95% CI)]

1 year

2 years

3 years

4 years

5 years

1 year

2 years

3 years

4 years

5 years

Male

1972-1976

8287

40 (39–41)

22 (21–23)

15 (14–16)

12 (11–13)

10 (9–11)

41 (40–42)

24 (23–25)

17 (16–18)

13 (12–14)

12 (11–13)

 

1980-1984

9484

40 (39–41)

26 (25-270

21 (20–23)

18 (17–19)

16 (15–17)

41 (40–42)

28 (27–29)

23 (22–24)

20 (19–21)

19 (18–20)

 

1988-1991

8134

42 (41–43)

29 (28–30)

24 (23–25)

22 (21–23)

20 (19–21)

44 (43–45)

31 (30–32)

27 (26–28)

25 (24–26)

24 (23–25)

 

2002-2003

7038

51 (50–52)

37 (36–38)

30 (29–31)

27 (26–28)

25 (24–26)

54 (53–55)

40 (39–41)

34 (33–35)

31 (30–32)

30 (29–31)

 

χ2*

 

135.90

266.87

378.96

444.63

485.62

-

-

-

-

-

 

P *

 

<0.001

<0.001

<0.001

<0.001

<0.001

-

-

-

-

-

Female

1972-1976

3860

38 (36–40)

20 (19–21)

14 (13–15)

11 (10–12)

10 (9–11)

39 (38–41)

21 (20–22)

15 (14–16)

12 (11–13)

11 (10–12)

 

1980-1984

4507

38 (37–39)

24 (23–25)

19 (18–20)

17 (16–18)

15 (14–16)

38 (37–39)

25 (24–26)

20 (19–21)

18 (17–19)

17 (16–18)

 

1988-1991

4224

39 (38–40)

27 (26–28)

22 (21–23)

20 (19–21)

19 (18–20)

40 (39–42)

28 (27–29)

24 (23–25)

23 (22–24)

22 (21–23)

 

2002-2003

3871

52 (50–54)

38 (36–40)

32 (31–34)

30 (29–31)

27 (26–28)

56 (54–58)

42 (40–44)

37 (36–39)

34 (33–36)

32 (31–34)

 

χ2*

 

154.65

277.26

308.62

344.42

316.50

-

-

-

-

-

 

P *

 

<0.001

<0.001

<0.001

<0.001

<0.001

-

-

-

-

-

*Logrank test was used to compare the survival rates.

Discussion

In this longitudinal study of gastric cancer based on Shanghai Cancer Registry database, we observed a declining trend of survival probability with the increase of patient’s age and clinical stages at the time of diagnosis. Long-term survival of gastric cancer varied among different tumor sites. The worst prognosis was observed in patients with cardia cancer. By using a long-term survival analysis on the longitudinal survival data from 1972 to 2003, we depicted that the survival probability of patients with gastric cancer in Shanghai has improved significantly during the last decades.

Gastric cancer remains a major public health issue ranking the fourth most common cancer and the second leading cause of cancer death worldwide [4]. National mortality surveys conducted in 1970s and 1990s in China, revealed an obvious cluster of geographical distribution of gastric cancer in the country, with the highest mortality mostly locating in rural areas, especially in the areas of the middle-western part of China. Despite a slight increase from the 1970s to the early 1990s, remarkable declines in gastric cancer mortality were noticed in almost the entire population in China. These declines were largely due to the dramatic improvements in the social-economic environment, lifestyle, nutrition, education, and health care system after economic reforms started decades ago [12]. Nevertheless, gastric cancer remains a cancer burden currently and be one of the key issues in cancer prevention and control strategy in China [12, 13].

Data from this study revealed that the survival rate of gastric cancer patients in Shanghai was still poor. It was a little higher than that of America and some European countries [1416], but much lower than that in Japan and Korea [1719]. In this study, we used both observed survival rate and relative survival rate to estimate the prognosis of gastric cancer. Relative survival rate which is calculated by dividing observed survival rate by expected survival rate is designed for cancer survival studies, in order to exclude the effect resulting from different background mortalities. The 5-years relative survival rate is commonly used to monitor the progress of cancer and it reasonably indicates the average survival experience of cancer patients in a given population [20]. During the last decades over the four observation periods of 1972–1976, 1980–1984, 1988–1991, and 2002–2003, the 5-years relative survival rate of gastric cancer increased from 12% to 30% among male patients and from 11% to 32% among female patients, which seemed to be more significant than those observed in the European countries [21].

Gender difference of long-term survival of gastric cancer was not obvious in Shanghai, which was similar to the findings from other studies [22]. The prognosis of gastric cancer is closely related to the stage of disease at diagnosis. In stage I, cancer has formed in the inside lining of the mucosa (innermost layer) of the stomach wall, whereas in stage IV, cancer has spread to distant parts of the body. Early gastric cancer, whereby disease is limited to mucosa and submucosa, confers a survival rate of greater than 90% in 5 years in many centers [23]. Our study further proved that the detection of gastric cancer in the early stage is vitally important in ensuring an excellent prognosis. Every effort needs to be made to facilitate the early diagnosis of gastric cancer with aims to prolong patient’s survival time and quality of life [23]. Epidemiologic evidence supports the classification of gastric cancer into two biologically distinct disease entities, those occurring proximally (cardia) and distally (noncardia). Though carcinomas of the cardia and stomach are frequently grouped together in epidemiologic statistics, they are clearly distinct diseases [24]. Epidemiological and clinical studies have led some authors to suggest that tumors located at the esophageal-gastric junction are distinct from other tumors located in the esophagus or distal stomach, with differing risk factors, tumor characteristics, and biological behavior [25, 26]. The association between tumor located at the esophageal-gastric junction and more advanced disease stage has been reported elsewhere and some authors have attributed these findings to more aggressive behavior of junctional tumor [26]. Junctional tumors are associated with adverse prognosis compared with other esophageal and gastric cancers. The anatomical site of these tumors potentially allows tumor spread to lymph nodes located above or below the diaphragm [27]. It is feasible that tumors located in cardia are more aggressive than the ones of distal stomach, and the former ones are usually diagnosed at advanced stage [28, 29]. Our study also demonstrated this situation that the 5-years relative survival rate of cardia cancer was the lowest compared with other tumor sites.

One strength of our study was that the databases were acquired from the Shanghai Cancer Registry, the oldest population based cancer registry in mainland China. The registry has contributed data on survival from cancer sites or types registered during 1988–1991 to the first volume of IARC publication on Cancer. Survival data obtained from a population-based cancer registry ideally portrays the average outcome of the disease which avoids the selective bias commonly appears in hospital sourced cases. Comparing to clinical survival study providing information about the treatment, the population-based survival study can evaluate the effectiveness of healthcare systems [30, 31]. Besides, population-based cancer registration is necessary to monitor cancer incidence and estimate cancer prevalence [32].

One limitation of this study is that there were 58.4% patients reported with unknown stages. It might be attributed to missing information or patients with unresected cancers. If these cases with unknown stages were gastric cancer patients unable to be surgically resected (so, without TNM stage), usually the survival rate was not far from that of patients with stage IV cases. In this study, their survival was not far from that of stage III, suggesting that most of cases correspond to missing information. Unfortunately, we couldn’t distinguish them based on the current database because all these patients were registered as NOS in the notification cards reported 10 years ago. Secondly, it has been reported that cancer site-related factors may influence the outcome. However, due to the retrospective nature of the present study, we failed to obtain all the needed information for the sites which could have contributed to the bias in estimating the survival rate and thus the influence on the outcome. Thirdly, in the present study, we chose the “classical” relative survival method for cancer survival estimation which may not correctly estimate the net survival, whenever a factor influences jointly the mortality due to cancer or the population life tables used for other-cause mortality. The “net” survival developed by Pohar et al. might be an alternative way used in the future to replace the relative survival in population-based studies [33].

Conclusions

In conclusion, the survival probability of patients with gastric cancer in Shanghai has improved significantly during the last decades. Age, stage and site of tumor have impacts on patient’s prognosis. Information from this study is useful for understanding survival differences that are influenced by changing prevention and treatment strategies.

Declarations

Acknowledgements

This work was supported by the funding from Shanghai Municipal Center for Disease Control and Prevention. The data of gastric cancer for this study were derived from the Shanghai Cancer Registry, compiled by the Shanghai Center for Disease Control and Prevention (CDC).

Authors’ Affiliations

(1)
Department of Oncology, Xin Hua Hospital affiliated to Shanghai Jiaotong University School of Medicine
(2)
Shanghai Municipal Center for Disease Control and Prevention

References

  1. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D: Global cancer statistics. CA Cancer J Clin. 2011, 61 (2): 69-90. 10.3322/caac.20107.View ArticlePubMedGoogle Scholar
  2. Fitzsimmons D, Osmond C, George S, Johnson CD: Trends in stomach and pancreatic cancer incidence and mortality in England and Wales, 1951–2000. Br J Surg. 2007, 94 (9): 1162-1171. 10.1002/bjs.5751.View ArticlePubMedGoogle Scholar
  3. Anderson WF, Camargo MC, Fraumeni JJ, Correa P, Rosenberg PS, Rabkin CS: Age-specific trends in incidence of noncardia gastric cancer in US adults. JAMA. 2010, 303 (17): 1723-1728. 10.1001/jama.2010.496.View ArticlePubMedPubMed CentralGoogle Scholar
  4. Crew KD, Neugut AI: Epidemiology of gastric cancer. World J Gastroenterol. 2006, 12 (3): 354-362.View ArticlePubMedPubMed CentralGoogle Scholar
  5. Jemal A, Siegel R, Ward E, Murray T, Xu J, Smigal C, Thun MJ: Cancer statistics, 2006. CA Cancer J Clin. 2006, 56 (2): 106-130. 10.3322/canjclin.56.2.106.View ArticlePubMedGoogle Scholar
  6. Ding YB, Xia TS, Wu JD, Chen GY, Wang S, Xia JG: Surgical outcomes for gastric cancer of a single institute in southeast China. Am J Surg. 2012, 203 (2): 217-221. 10.1016/j.amjsurg.2010.10.022.View ArticlePubMedGoogle Scholar
  7. Xiang YB, Jin F, Gao YT: Cancer survival in Shanghai, China, 1992–1995. IARC Sci Publ. 2011, 162: 55-68.PubMedGoogle Scholar
  8. Gao Y, Lu W: Cancer incidence, mortality and survival rates in urban Shanghai (1973–2000). 2007, Shanghai: Second Military Medical University PressGoogle Scholar
  9. Swaminathan R, Lucas E, Sankaranarayanan R: Cancer survival in Africa, Asia, the Caribbean and Central America: database and attributes. IARC Sci Publ. 2011, 162: 23-31.PubMedGoogle Scholar
  10. World Health Organization: 10th revision, Volume 1. Manual of the International Statistical Classification of Diseases, Injuries, and Causes of Death. 1992, Geneva, Switzerland: World Health OrganizationGoogle Scholar
  11. Bao PP, Lu W, Cui Y, Zheng Y, Gu K, Chen Z, Zheng W, Shu XO: Ginseng and Ganoderma lucidum use after breast cancer diagnosis and quality of life: a report from the Shanghai Breast Cancer Survival Study. PLoS One. 2012, 7 (6): e39343-10.1371/journal.pone.0039343.View ArticlePubMedPubMed CentralGoogle Scholar
  12. Wang JM, Xu B, Hsieh CC, Jiang QW: Longitudinal trends of stomach cancer and esophageal cancer in Yangzhong County: a high-incidence rural area of China. Eur J Gastroenterol Hepatol. 2005, 17 (12): 1339-1344. 10.1097/00042737-200512000-00012.View ArticlePubMedGoogle Scholar
  13. Yang L: Incidence and mortality of gastric cancer in China. World J Gastroenterol. 2006, 12 (1): 17-20.View ArticlePubMedPubMed CentralGoogle Scholar
  14. Sant M, Aareleid T, Berrino F, Bielska LM, Carli PM, Faivre J, Grosclaude P, Hedelin G, Matsuda T, Moller H, Moller T, Verdecchia A, Capocaccia R, Gatta G, Micheli A, Santaquilani M, Roazzi P, Lisi D: Eurocare Working Group: survival of cancer patients diagnosed 1990–94–results and commentary. Ann Oncol. 2003, 14 (Suppl 5): v61-v118.View ArticlePubMedGoogle Scholar
  15. Brenner H, Francisci S, de Angelis R, Marcos-Gragera R, Verdecchia A, Gatta G, Allemani C, Ciccolallo L, Coleman M, Sant M: Long-term survival expectations of cancer patients in Europe in 2000–2002. Eur J Cancer. 2009, 45 (6): 1028-1041. 10.1016/j.ejca.2008.11.005.View ArticlePubMedGoogle Scholar
  16. Brenner H, Gondos A, Arndt V: Recent major progress in long-term cancer patient survival disclosed by modeled period analysis. J Clin Oncol. 2007, 25 (22): 3274-3280. 10.1200/JCO.2007.11.3431.View ArticlePubMedGoogle Scholar
  17. Tsukuma H, Ajiki W, Ioka A, Oshima A: Survival of cancer patients diagnosed between 1993 and 1996: a collaborative study of population-based cancer registries in Japan. Jpn J Clin Oncol. 2006, 36 (9): 602-607. 10.1093/jjco/hyl068.View ArticlePubMedGoogle Scholar
  18. Inoue M, Tsugane S: Epidemiology of gastric cancer in Japan. Postgrad Med J. 2005, 81 (957): 419-424. 10.1136/pgmj.2004.029330.View ArticlePubMedPubMed CentralGoogle Scholar
  19. Shin A, Kim J, Park S: Gastric cancer epidemiology in Korea. J Gastric Cancer. 2011, 11 (3): 135-140. 10.5230/jgc.2011.11.3.135.View ArticlePubMedPubMed CentralGoogle Scholar
  20. Parker SL, Tong T, Bolden S, Wingo PA: Cancer statistics, 1996. CA Cancer J Clin. 1996, 46 (1): 5-27. 10.3322/canjclin.46.1.5.View ArticlePubMedGoogle Scholar
  21. Verdecchia A, Guzzinati S, Francisci S, de Angelis R, Bray F, Allemani C, Tavilla A, Santaquilani M, Sant M: Survival trends in European cancer patients diagnosed from 1988 to 1999. Eur J Cancer. 2009, 45 (6): 1042-1066. 10.1016/j.ejca.2008.11.029.View ArticlePubMedGoogle Scholar
  22. Cook MB, McGlynn KA, Devesa SS, Freedman ND, Anderson WF: Sex disparities in cancer mortality and survival. Cancer Epidemiol Biomarkers Prev. 2011, 20 (8): 1629-1637. 10.1158/1055-9965.EPI-11-0246.View ArticlePubMedPubMed CentralGoogle Scholar
  23. Tan YK, Fielding JW: Early diagnosis of early gastric cancer. Eur J Gastroenterol Hepatol. 2006, 18 (8): 821-829. 10.1097/00042737-200608000-00004.View ArticlePubMedGoogle Scholar
  24. Schlansky B, Sonnenberg A: Epidemiology of noncardia gastric adenocarcinoma in the United States. Am J Gastroenterol. 2011, 106 (11): 1978-1985. 10.1038/ajg.2011.213.View ArticlePubMedGoogle Scholar
  25. Rudiger SJ, Feith M, Werner M, Stein HJ: Adenocarcinoma of the esophagogastric junction: results of surgical therapy based on anatomical/topographic classification in 1,002 consecutive patients. Ann Surg. 2000, 232 (3): 353-361. 10.1097/00000658-200009000-00007.View ArticleGoogle Scholar
  26. Deans C, Yeo MS, Soe MY, Shabbir A, Ti TK, So JB: Cancer of the gastric cardia is rising in incidence in an Asian population and is associated with adverse outcome. World J Surg. 2011, 35 (3): 617-624. 10.1007/s00268-010-0935-0.View ArticlePubMedGoogle Scholar
  27. Peters CJ, Hardwick RH, Vowler SL, Fitzgerald RC: Generation and validation of a revised classification for oesophageal and junctional adenocarcinoma. Br J Surg. 2009, 96 (7): 724-733. 10.1002/bjs.6584.View ArticlePubMedGoogle Scholar
  28. Ramos-De LMA, Salgado-Nesme N, Torres-Villalobos G, Medina-Franco H: Clinicopathologic characteristics of gastric cancer in a young patient population. J Gastrointest Surg. 2004, 8 (3): 240-244. 10.1016/j.gassur.2003.12.009.View ArticleGoogle Scholar
  29. Roy P, Piard F, Dusserre-Guion L, Martin L, Michiels-Marzais D, Faivre J: Prognostic comparison of the pathological classifications of gastric cancer: a population-based study. Histopathology. 1998, 33 (4): 304-310. 10.1046/j.1365-2559.1998.00534.x.View ArticlePubMedGoogle Scholar
  30. Micheli A, Berrino F, Paci E, Verdecchia A, Pierottis MA: Strategies for cancer control in Italy. Tumori. 2007, 93 (4): 329-336.PubMedGoogle Scholar
  31. Micheli A, Capocaccia R, Martinez C, Mugno E, Coebergh JW, Baili P, Verdecchia A, Berrino F, Coleman M: Cancer control in Europe: a proposed set of European cancer health indicators. Eur J Public Health. 2003, 13 (3 Suppl): 116-118.View ArticlePubMedGoogle Scholar
  32. Berrino F, Verdecchia A, Lutz JM, Lombardo C, Micheli A, Capocaccia R: Comparative cancer survival information in Europe. Eur J Cancer. 2009, 45 (6): 901-908. 10.1016/j.ejca.2009.01.018.View ArticlePubMedGoogle Scholar
  33. Perme MP, Stare J, Esteve J: On estimation in relative survival. Biometrics. 2012, 68 (1): 113-120. 10.1111/j.1541-0420.2011.01640.x.View ArticlePubMedGoogle Scholar
  34. Pre-publication history

    1. The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2407/14/300/prepub

Copyright

© Zheng et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.