Multiple primary cancers in men with sporadic or familial prostate cancer: Its clinical implications

Objective: To evaluate the risk of concordant cancers in patients with prostate cancer (CaP) and examine whether this risk differed according to family history of CaP. Materials and methods: We examined 1,102 patients with CaP, having prospectively acquired pedigrees, and analyzed information regarding multiple primary cancers. The prevalence of concordant cancers was assessed with respect to the family history of CaP. First-degree familial CaP was defined as a positive history of CaP in first-degree relatives (parents, siblings, and offspring). Odds ratios for each concordant cancer in men with first-degree familial CaP were estimated. Clinical characteristics were compared between men with and without concordant cancers. Results: The prevalence of multiple primary cancers in sporadic PCa was 12.0%, similar to that of first-degree familial CaP (13.5%, P = 0.698). Gastrointestinal cancer was the most common concordant cancer (3.6%), followed by colorectal (2.9%), lung (1.5%), urothelial (1.3%), kidney (1.1%), and other cancers. Colorectal cancer was more frequent in first-degree familial CaP than in sporadic disease (6.8 vs. 2.7%, P = 0.045). However, the rates of other concordant cancers were similar between the 2 groups (P range, 0.242–0.963). Compared with sporadic disease, the age-adjusted odds ratio for concordant colorectal cancer in first-degree familial CaP was 2.930 (95% confidence interval, 1.082–7.929). Patients with concordant colorectal cancer had fewer (2.8 vs. 3.9 cores, P = 0.041) and a lower percentage of (23.5 vs. 33.1%, P = 0.030) positive biopsy cores than CaP only patients. Conclusions: A family history of CaP was significantly associated with a risk of concordant colorectal cancer. These findings imply that some CaP shares a genetic pathogenesis with colorectal cancer.