Purpose: Patients with colorectal cancer have an increased risk for developing synchronous and metachronous neoplasms. However, besides those cases with inherited disorders predisposing to tumor multicentricity, it is unknown which patients are prone to this condition. This study was designed to identify individual and familial characteristics associated with the development of synchronous colorectal neoplasms in patients with colorectal cancer.
Methods: During a one-year period, all patients with colorectal cancer attended in 25 Spanish hospitals were included. Exclusion criteria were colorectal cancer developed in the context of familial adenomatous polyposis or inflammatory bowel disease, refusal to participate in the study, incomplete family history, and inadequate examination of the colon and rectum. In addition to demographic, clinical, pathology, molecular (microsatellite instability status), and familial characteristics, presence of synchronous colorectal neoplasms (adenoma or carcinoma) were analyzed.
Results: A total of 1,522 patients were included in the study. Synchronous colorectal neoplasms were documented in 505 patients (33.2 percent): adenoma (n = 411), carcinoma (n = 27), or both (n = 67). Development of these lesions was associated with male gender (odds ratio, 1.94; 95 percent confidence interval, 1.43-2.65), personal history of colorectal adenoma (odds ratio, 3.39; 95 percent confidence interval, 1.58-7.31), proximal location of primary tumor (odds ratio, 1.40; 95 percent confidence interval, 1.02-1.94), tumor TNM Stage II (odds ratio, 1.31; 95 percent confidence interval, 1.15-4.66), mucinous carcinoma (odds ratio, 1.89; 95 percent confidence interval, 1.19-2.99), and family history of gastric cancer (odds ratio, 2.03; 95 percent confidence interval, 1.17-3.52).
Conclusions: Based on individual and familial characteristics associated with synchronous colorectal neoplasms, it has been possible to identify a subgroup of patients with colorectal cancer prone to tumor multicentricity with potential implications on the delineation of preventive strategies.