Comparison of prognosis in cancer of the colon and rectum

To determine whether there is a difference in prognosis between colon and rectal cancer.

A prospective audit was conducted of a cohort of consecutive patients presenting to a single colorectal surgeon over an 8-year period, in a teaching hospital colorectal unit. There were 492 patients, 274 with colon cancer and 218 with rectal cancer, followed up to death or for a median of 43 months. Resection of all macroscopic disease was performed where possible by performing, if necessary, en bloc excision of local disease in continuity with adjacent involved structures. There was total mesorectal excision for middle and lower third rectal cancers. The main outcome measures were local recurrence, any recurrence, and survival.

Five year survival excluding non-colorectal cancer deaths was 80% for colon cancer and 70% for rectal cancer after curative excision when all stages were grouped together (logrank P=0.25). Survival curves for Dukes' A and B cancers at each site were the same. Dukes' C rectal cancers recurred locally more frequently than colon cancers, but there was no significant difference in survival.

With appropriate radical surgery, survival after curative resection of rectal cancer can be as favourable as for colon cancer. Patients with Dukes' C cancers of the rectum are more at risk of local recurrence and this group should be the focus of efforts to improve outcome further.