Adjuvant aspirin use associated with improved survival for colorectal cancer
Regular aspirin use after colorectal cancer diagnosis lowered disease-specific mortality by 29% and overall mortality by 21%, according to the results of a prospective cohort study.
Participants in the cohort (n=1,279) were medical professionals diagnosed with stage I to III colorectal cancer. All were recruited into cohorts prior to diagnosis.
The researchers observed 35% total mortality and 15% disease-specific mortality in the participants who used aspirin after diagnosis compared with 39% total mortality and 19% disease-specific mortality in the nonaspirin group. Five-year OS was 88% in the aspirin group vs. 83% in the nonaspirin group. Ten-year OS was 74% vs. 69% in favor of the aspirin group.
The researchers said regular use of aspirin following diagnosis was associated with improved overall mortality (HR=0.79; 95% CI, 0.65-0.97) and disease-specific mortality (HR=0.71; 95% CI, 0.53-0.95). They added that the relationship remained even after removing stage I participants.
Aspirin use prior to diagnosis did not appear to affect either overall mortality (HR=0.93; 95% CI, 0.77-1.11) or disease-specific mortality (HR=1.05; 95% CI, 0.80-1.37).
"Among the 459 participants for whom we had sufficient tumor tissue with adjacent normal mucosa to assay for COX-2, the benefit of aspirin use after diagnosis appeared to be confined to those with COX-2-positive primary tumors," the researchers wrote.
Regular aspirin use among participants with COX-2-positive tumors further lowered risk for colorectal cancer-specific mortality (HR=0.39; 95% CI, 0.20-0.76) and overall mortality (HR=0.62; 95% CI, 0.42-0.93). Mortality risk was not lowered in participants with COX-2-negative tumors.
In an accompanying editorial, Alfred I. Neugut, MD, PhD, co-director of the Cancer Prevention Center at New York Presbyterian Hospital, said these findings may have uncovered a use for aspirin in the adjuvant setting.
“In the study by Chan et al, the survival benefits of aspirin were similar in patients who received standard adjuvant chemotherapy and those who did not, and in patients with stage I and stage II disease as well as those who had stage III disease at diagnosis,” Neugut wrote. “Thus, aspirin may have the potential to be useful as adjuvant therapy, not just for locally advanced disease but for early stage patients as well. Further studies are needed to confirm and extend these findings, and should also investigate the use of aspirin as an agent in individuals with metastatic disease.”
Chan AT. JAMA. 2009;302:649-659.
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