Approximately 5–10% of pancreatic carcinoma (PC) patients report a family history of the disease. In some families, mutations of tumor suppressor genes have been elucidated, but for most the causative gene remains unidentified. Counseling the families of PC patients regarding their risk of cancer remains problematic because little information is available.
The authors analyzed family history questionnaires completed by 426 unselected, sequential Mayo Clinic patients with PC. The prevalence of malignancy reported among 3355 of their first-degree relatives was compared with the Surveillance, Epidemiology, and End Results Project (SEER) 9 (2000) registry. Age-adjusted and gender-adjusted standardized incidence ratios (SIRs) were generated.
Greater than 130,000 person-years at risk for cancer among the first-degree relatives were analyzed. The risk of PC was found to be increased among the first-degree relatives of patients with PC (SIR of 1.88; 95% confidence interval [95% CI], 1.27–2.68), as was the risk of liver carcinoma (SIR of 2.70; 95% CI, 1.51–4.46). Lymphoma (SIR of 0.28; 95% CI, 0.12–0.55), bladder carcinoma (SIR of 0.55; 95% CI, 0.31–0.89), breast carcinoma (SIR of 0.73; 95% CI, 0.57–0.92), lung carcinoma (SIR of 0.62; 95% CI, 0.47–0.80), and prostate carcinoma (SIR of 0.71; 95% CI, 0.54–0.92) were found to be underrepresented. When the proband was age < 60 years, the risk of PC to first-degree relatives was found to be increased further (SIR of 2.86; 95% CI, 1.15–5.89). In this subgroup, no other malignancies were found to be significantly increased, although the risks of melanoma (SIR of 1.73; 95% CI, 0.70–3.57), ovarian carcinoma (SIR of 2.20; 95% CI, 0.72–5.12), and colon carcinoma (SIR of 1.37; 95% CI, 0.80–2.19) were suggestive.
There was a nearly twofold increased risk of PC in the first-degree relatives of PC probands. This risk was found to increase nearly threefold when patients were diagnosed before age 60 years. At the current time, in the absence of a pedigree suggestive of known familial cancer syndromes, the current study results do not support targeted screening for other malignancies in the first-degree relatives of patients with sporadic PC. Cancer 2005. © 2005 American Cancer Society.