Colorectal cancer before the age of 40: a case-control study.

PURPOSE: Colorectal adenocarcinoma before the age of 40 is uncommon, and its prognosis is controversial, with many studies reporting a worse prognosis than in older patients and others showing no difference. The current study compared two groups of patients who had surgical resection for colorectal adenocarcinoma.
METHODS: The case group was composed of 34 patients younger than 40 (34 +/- 4) years. Detailed pathologic prognosis factors, tumor cell proliferation measured by proliferating cell nuclear antigen, survival, family history, and predisposing conditions were analyzed. Results were compared with a control group constituted of 34 patients older than 65 (75 +/- 6) years matched by gender, cancer site, and Dukes stage.
RESULTS: Tumor differentiation, presence of vascular and perineural neoplastic invasion, tumor growth pattern, tumor cell proliferation measured by proliferating cell nuclear antigen count, and survival according to the Kaplan-Meier method were not significantly different between younger and older patients. The only difference between the two groups was a higher prevalence of family history and predisposing conditions for colorectal cancer in younger patients (23 vs. 3 percent; P = 0.03).
CONCLUSION: This case-control study documents that pathologic features and prognosis of colorectal adenocarcinoma are comparable in patients younger than 40 years compared with older patients for identical stages. The higher prevalence of positive family history in younger patients suggests a different genetic background compared with older patients.