Changing patterns of recurrence after treatment for colorectal cancer.

Background: The management of patients with colorectal cancer has changed appreciably over the last 16 years. The aims of this study were to compare the rates and patterns of disease recurrence over the last 10 years with a historical control group.

Materials And Methods: Data was obtained from a prospective database that had recorded all patients presenting with colorectal cancer from 1996 to 2006. This data was compared with a retrospective data set that included all patients treated with colorectal cancer at the same institution from 1989 to 1995. The Kaplan-Meier technique was used to calculate the 5 year recurrence and local recurrence rates for the two groups.

Results: There were 710 patients in the study group and 475 patients in the control group. There were more patients with rectal cancer and stage I cancer in the study group. When comparing the study group vs the control group, there was an increase in the time to recurrence (2.1 vs 1.6 years, n.s.) and a decrease in the 5 year recurrence rate for patients undergoing curative resections (17% [95% CI 12%-20%] vs 42% [95% CI 36%-49%], p < 0.001). These changes were noted for both colon (16% vs 34%, p < 0.001) and rectal cancers (18% vs 50%, p < 0.001). There was also a decrease in local recurrence in patients with rectal cancer (8.8% [95% CI 4.5%-13.1%] vs 33.6% [95% CI 23.6%-43.6%], p < 0.001).

Conclusions: Within this institution, there has been a significant trend during the last 16 years towards reduced disease recurrence, both local and metastatic, and a prolongation in the time to develop recurrence.