Colorectal adenocarcinoma in patients less than 40 years of age. From 1973 to 1985, 105 patients under 40 years of age were treated for colorectal adenocarcinoma at Roswell Park Cancer Institute. There were 51 males and 54 females. The mean age was 32 years. The majority of patients were treated for left colon or rectal carcinomas. Ninety-seven of 105 patients underwent surgical resection of their primary cancer, 70 (67 percent) of which were potentially curative. Twenty-seven patients underwent palliative resections. Dukes' A or B lesions were not seen in patients less than 20 years old, whereas these early lesions were seen in 11 percent of patients 20 to 29 years old and in 26 percent of patients greater than 30 years of age. The mean survival for patients between 20 and 29 years was 39 months and 46 months for patients 30 years and older. 