In a French retrospective study reported by David Tougeron, MD, PhD, of Poitiers University Hospital, Poitiers, France, and colleagues in the Journal of the National Cancer Institute, the addition of adjuvant oxaliplatin to fluoropyrimidine treatment improved disease-free survival in patients with stage III deficient mismatch repair colon cancer.
The study included 433 consecutive patients undergoing curative surgical resection for stage II or III deficient mismatch repair colon cancer between 2000 and 2011 at 11 French centers. Of them, 56.8% had stage II, and 43.2% had stage III disease. Patients received surgery alone (n = 263) or surgery with chemotherapy consisting of fluoropyrimidine with (n = 119) or without (n = 51) oxaliplatin. Adjuvant chemotherapy was given to 6.7% of patients with stage II disease (mainly those with high-risk disease) and 69.0% of patients with stage III disease.
Improved Disease-Free Survival
Mean follow-up was 47.0 months. On multivariate analysis, compared with surgery alone, oxaliplatin-based chemotherapy was associated with significantly improved disease-free survival (hazard ratio [HR] = 0.35, P < .001), whereas improvement with fluoropyrimidine treatment alone was not significant (HR = 0.73, P = .38).
In a subgroup analysis, the disease-free survival benefit of oxaliplatin-based chemotherapy was significant only among patients with stage III disease (HR = 0.41, P = .02). Among high-risk stage II patients, hazard ratios were 0.13 (P = .06) with oxaliplatin-based treatment and 0.85 (P = .83) with fluoropyrimidine treatment alone.
The investigators concluded: “This study supports the use of adjuvant chemotherapy with fluoropyrimidine plus oxaliplatin in stage III deficient mismatch repair [colon cancer].” ■