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Second Primary Colorectal Cancer: The Consequence of Management Failure at Several Potential Levels
Patients with previously diagnosed colorectal cancer are thought to be at increased risk for second primary large-bowel cancer (1-3). Widely endorsed surveillance guidelines promote regular colonoscopic evaluations after initial cancer resection in this high-risk group (4, 5). Given the generally accepted progression from adenoma to carcinoma, an effective surveillance strategy would identify and remove both preinvasive and early invasive neoplasms so that cancer might be prevented or detected before metastasizing. However, few data have been available to evaluate the effectiveness of current approaches to postoperative surveillance in reducing the risk for and from subsequent colorectal cancer.
In this issue, Green and colleagues (6) report their findings from a historical cohort study designed to determine the incidence of second primary colorectal cancer among patients with resected stage II or stage III colonic malignancies when intensive surveillance was attempted. The study involved 3278 patients who participated in a multi-institutional adjuvant chemotherapy trial (Intergroup 0089) (7). During 15 345 person-years of follow-up, the observed rate of second primary colorectal cancer was 274 cases per 100 000 person-years, a rate significantly higher than that expected based on data from either the Surveillance, Epidemiology, and End Results program (8) (standardized incidence ratio, 1.6 [95% CI, 1.2 to 2.2]) or the National Polyp Study (9) (standardized incidence ratio, 6.8 [CI, 2.7 to 22.0]). The authors concluded that the incidence of second primary colorectal cancer remains high despite intensive surveillance strategies. This alarming conclusion warrants careful scrutiny and should be assessed to determine potential explanations about how existing evaluation and surveillance strategies may be falling …
