As reported by Hua et al in the Journal of Clinical Oncology, long-term survivors of colorectal cancer with KRAS wild-type tumors had improved survival with regular use of any nonsteroidal anti-inflammatory drug (NSAID) post diagnosis.
The study involved data from 2,149 patients aged 18 to 74 years diagnosed with incident colorectal cancer from 1997 to 2008 identified from several population-based cancer registries in the United States, Canada, and Australia. Detailed epidemiologic questionnaires were completed at study enrollment and at 5 years. Survival was assessed through linkage to national death registries. Regular use of NSAIDs was defined as use at least twice per week for more than 1 month. Ever users were patients who regularly used the medications, and nonusers were those who used the medications other than regularly or never used them.
Effect of Aspirin Use
After median follow-up of 10.8 years, death had occurred in 381 patients, with 100 due to colorectal cancer. Compared with nonusers, postdiagnostic aspirin-only users had improved overall survival (hazard ratio [HR] = 0.75, 95% confidence interval [CI] = 0.59–0.95) and colorectal cancer–specific survival (HR = 0.44, 95% CI = 0.25–0.71); the benefits were more pronounced among patients initiating aspirin use after diagnosis, with hazard ratios of 0.64 (95% CI = 0.47–0.86) for overall survival and 0.40 (95% CI = 0.20–0.80) for colorectal cancer–specific survival.
Use of Any NSAID
Regular use of any NSAID after diagnosis was associated with improved overall survival (HR = 0.76, 95% CI = 0.62–0.94); however, significance was lost among users of nonaspirin NSAIDs and among those who used both aspirin and other NSAIDs. No significant associations were observed between colorectal cancer–specific survival and regular use of other NSAIDs only or regular use of both aspirin and other NSAIDs.
The association between postdiagnosis use of any NSAID and overall survival differed significantly according to KRAS mutation status (P = .01 for interaction). Overall survival was improved with use of any NSAID among participants with KRAS wild-type tumors (HR = 0.60, 95% CI = 0.46–0.80) but not among those with KRAS-mutant tumors (HR = 1.24, 95% CI = 0.78–1.96). A similar association was observed for colorectal cancer–specific survival, although it did not reach significance (P = .08 for interaction); hazard ratios for colorectal cancer–specific survival with any NSAID use were 0.54 (95% CI = 0.30–0.95) for KRAS wild-type and 0.96 (95% CI = 0.42–2.21) for KRAS-mutant status.
The investigators concluded: “Among long-term [colorectal cancer] survivors, regular use of NSAIDs after [colorectal cancer] diagnosis was significantly associated with improved survival in individuals with KRAS wild-type tumors.”
The study was supported by the National Cancer Institute and through cooperative agreements with numerous colon cancer family registry centers.
Polly A. Newcomb, PhD, of Fred Hutchinson Cancer Research Center, is the corresponding author of the Journal of Clinical Oncology article.
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