Survival outcomes with addition of celecoxib to adjuvant chemotherapy for stage III colon cancer: impact of PIK3CA mutation status

The multinational phase 3 CALGB/SWOG 80702 trial evaluated addition of celecoxib versus placeb to standard adjuvant chemotherapy for stage 3 colon cancer, and found no effect of this addition in terms of disease-free survival. A preplanned subgroup analysis of the trial has now been published. Among patients with tumor with PIK3CA gain-of-function mutations, the aHR of disease-free survival with celecoxib versus placebo was 0.56 (95% CI 0.33-0.96), whereas it was 0.89 (0.70-1.14) among patients without these mutations, although the interaction test was nonsignificant (p=0.13). The overall survival was similarly improved among patients with PIK3CA gain-of-function mutations (celecoxib versus placebo: aHR 0.44; 95% CI 0.22-0.85) but not among patients without these mutations (0.94; 0.68-1.30; p for interaction 0.04). The authors conclude that these results suggest potential utility of analysis of PIK3CA mutation status to consider use of COX-2 inhibitors to standard adjuvant chemotherapy for stage III colon cancer.