(HealthDay News) — 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.


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“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.

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