Table 1 Characteristics of the studies selected for the systematic review

Number of studies

54 studies

42 studies

49 studies

Number of models

58 models

42 models

17 models

Year of publication

1982–2016

1982–2016

1987–2016

 Prospective

2 studies

2 studies

0 study

 Retrospective

32 studies

23 studies

30 studies

 Unknown

20 studies

18 studies

19 studies

 Population-based

14 studies

11 studies

12 studies

 Hospital-based

31 studies

29 studies

33 studies

 RCT-based

6 studies

1 study

4 studies

 Unknown

3 studies

2 studies

0 study

Sample size

75–433,272

30–433,272

48–387,262

 Deaths

27–24,610

27–24,610

11–3902

 Recurrences

5–1030

5–950

9–1188

 Europe

24 studies

22 studies

29 studies

 North America

13 studies

8 studies

7 studies

 Asia

11 studies

10 studies

11 studies

 Others

2 studies (Australia)

0 study

3 studies (1 Australia. 1 New Zealand, 1 Brazil)

 Adhere to good practice

1 study

1 study

0 study

 Large sample size

2 studies

2 studies

4 studies

 Patients diagnosed recently

1 study

1 study

0 study

 Homogeneous source of data

2 studies

2 studies

1 study

 Low proportion of missing data

0 study

0 study

1 study

 Missing data

11 studies

11 studies

8 studies

 Small sample size

3 studies

3 studies

9 studies

 Patients treated with obsolete methods

4 studies

4 studies

3 studies

 Heterogeneous source of data

3 studies

3 studies

0 study

 Selection bias

2 studies

2 studies

0 study

 Short-time follow-up

1 study

1 study

0 study