Background: The impact of postoperative adjuvant chemotherapy on the oncological outcomes for stage II colorectal cancer remains controversial.
Methods: The literature was searched for studies published between 1985 and 2010 in which patients with stage II colorectal cancer were randomly assigned to receive either surgery combined with postoperative adjuvant chemotherapy or surgery alone. End points included 5-year overall survival, 5-year disease-free survival, recurrence, and mortality.
Results: A significant improvement in 5-year overall survival was associated with surgery combined with postoperative adjuvant chemotherapy for stage II colon cancer (hazard ratio, 0.81; 95% confidence interval (CI), 0.71-0.91) and for stage II rectal cancer (hazard ratio, 0.72; 95% CI, 0.61-0.86). The 5-year disease-free survival also favored the group of surgery combined with postoperative adjuvant chemotherapy for stage II colon cancer (hazard ratio, 0.86; 95% CI, 0.75-0.98) and for stage II rectal cancer (hazard ratio, 0.34; 95% CI, 0.22-0.51). For stage II colon cancer, a significant reduction in risk of recurrence was found in favor of postoperative adjuvant chemotherapy (risk ratio, 0.82; 95% CI, 0.71-0.95).
Conclusions: Postoperative adjuvant chemotherapy for stage II colorectal cancer appears to be associated with improved 5-year overall survival and 5-year disease-free survival, and reduction in risk of recurrence.