Smoking worsens outcomes with advanced colon cancer

(HealthDay)—Smoking is tied to significantly shorter disease-free survival (DFS) and time to recurrence (TTR) in patients undergoing treatment for stage III colon cancer, according to a study published April 1 in the Journal of Clinical Oncology.

Amanda Phipps, Ph.D., from the Fred Hutchinson Cancer Research Center in Seattle, Wash., and colleagues surveyed patients participating in a randomized adjuvant trial (infusional fluorouracil, leucovorin, and oxaliplatin [FOLFOX] or FOLFOX plus cetuximab). A total of 1,968 patients were questioned on smoking history and other risk factors.

The researchers found that ever-smokers experienced significantly shorter DFS, compared with never-smokers (three-year DFS proportion 70 percent versus 74 percent; hazard ratio [HR], 1.21). Even after adjusting for other variables, this association persisted (HR, 1.23), although there was significant interaction in this association based on BRAF mutation status in patients with BRAF wild-type, smoking was associated with shorter DFS (HR, 1.36) but not BRAF mutated (HR, 0.80; 95 percent confidence interval [CI], 0.50 to 1.29) colon cancer. In those with KRAS mutated versus KRAS wild-type colon cancer there was a stronger associated between smoking and poorer DFS (HR, 1.50 versus HR, 1.09 [95 percent CI, 0.85 to 1.39]), although interaction by KRAS mutation status was not statistically significant (P = .07). Similar associations were seen with TTR analysis.

"Overall, smoking was significantly associated with shorter DFS and TTR in patients with colon cancer," the authors write.
Several authors report financial ties to the diagnostics industry.