Familial risk associated with lung cancer as a second primary malignancy in first-degree relatives

BMC Cancer

Table 1 Lung cancer risk among individuals who had one first-degree relative affected by LCa-1 or LCa-2

Category	Cancer diagnosis in FDR								Comparison^c (LCa-1 vs. LCa-2)
	LCa-1				LCa-2				Comparison^c (LCa-1 vs. LCa-2)
	Age at diagnosis of LCa in FDR	N^a	RR^b	95%CI	Age at diagnosis of LCa in FDR	N^a	RR^b	95%CI	P1	P2
Overall	66 (59–73)	1474	1.96	1.85–2.07	71 (65–77)	161	1.89	1.62–2.21	0.56	0.93
Age in relative with LCa
≤ 60 years old	55 (49.5–58)	321	2.34	2.09–2.62	56 (51–58)	15	2.55	1.54–4.23	0.70	0.93
> 60 years old	70 (65–76)	1153	1.87	1.76–1.99	72 (68–78)	146	1.84	1.56–2.17	0.69	0.90
Type of family history
Only father	67 (60–74)	707	1.74	1.61–1.88	73 (66–78)	57	1.40	1.08–1.81	0.07	0.30
Only mother	66 (58–73)	321	1.95	1.74–2.18	70 (63–77)	39	1.81	1.33–2.49	0.51	0.71
Only brother	63 (56–69)	215	2.21	1.93–2.53	68 (61–72)	28	2.84	1.96–4.11	0.35	0.34
Only sister	62 (55–68)	236	2.64	2.33–3.01	67 (61–77)	37	2.90	2.10–4.00	0.60	0.53
Time between first primary cancer and LCa-2 in FDR
< 26 months					70 (63–75)	36	1.53	1.10–2.12
26–73 months					71 (65–77)	36	1.85	1.34–2.57
74–152 months					71 (65–77)	46	2.16	1.62–2.90
> 152 months					72 (66–78)	43	2.07	1.54–2.78

LCa lung cancer, LCa-1 Lung cancer as a first primary malignancy, LCa-2 Lung cancer as a second primary malignancy, FDR First-degree relative, RR Relative risk, 95%CI 95% confidence interval
^aN, number of LCa cases diagnosed during the follow-up
^bRR was estimated from Poisson regression using individuals without cancer family history as the reference. The covariates adjusted in the model included age groups (5 years), periods (5 years), hospitalization due to COPD, alcoholism and obesity, socioeconomic status (blue-collar worker, white-collar worker, farmer, private business, professional, or other/unspecified) and place of residence (big cities, northern Sweden, southern Sweden and unspecific)
^cComparison of familial risks associated with family history of LCa-1 and LCa-2 with Poisson regression. P1 is the p value for the comparison when the adjusted covariates were same as main analysis (above). P2 is the p value for the comparison when age at diagnosis of LCa in FDR (5-year group) and family relationship were additionally adjusted

ISSN: 1471-2407