Therapeutic approaches for patients with coexisting familial adenomatous polyposis and colorectal cancer

Objective: Colorectal cancer is a major cause of death in patients with familial adenomatous polyposis. Despite evidence for prophylactic colectomy, there is no ideal therapy for patients with coexisting familial adenomatous polyposis and colorectal cancer. We evaluated the correlation between surgery for familial adenomatous polyposis and multimodal treatment for colorectal cancer, and clarified prognosis of Japanese patients with familial adenomatous polyposis and colorectal cancer. Methods: We retrospectively reviewed data from 303 patients who underwent colorectal surgery for familial adenomatous polyposis between 2000 and 2012. Results: Overall, 172 patients had colorectal cancer. The most common procedure for familial adenomatous polyposis was restorative proctocolectomy with ileal pouch anal anastomosis, irrespective of colorectal cancer. Partial colectomy was more frequent in patients with than without colorectal cancer (8.7% and 0%, respectively). Ileal pouch anal anastomosis was frequently (60.6%) performed in patients with Stage I-III colorectal cancer. Overall, 12 of 20 patients with Stage IV colorectal cancer underwent metastasectomy; six patients simultaneously and six metachronously. There were fewer cases of ileal pouch anal anastomosis, but more total colectomy with ileorectal anastomosis was performed metachronously, compared with simultaneous metastasectomy (P = 0.006). More cytotoxic (P = 0.006) and molecular (P = 0.03) agents were administered to the ileorectal anastomosis/partial colectomy patients, compared with total proctocolectomy/ileal pouch anal anastomosis patients. A 5-year overall survival was 100% in Stage 0/I, 89.8% in Stage II, 87.9% in Stage III and 48.4% in Stage IV. Conclusions: In patients with familial adenomatous polyposis and colorectal cancer, primary surgery, metastasectomy and chemotherapy could be compatible with standard surgical approaches for familial adenomatous polyposis. However, modifying surgical procedures for familial adenomatous polyposis might help multimodality therapy for Stage IV colorectal cancer to prolong survival.