Aspirin use and survival after diagnosis of colorectal cancer.
BACKGROUND
Aspirin reduces risk of colorectal neoplasia in randomized trials and inhibits tumor growth and metastases in animal models. However, the influence of aspirin on survival after diagnosis of colorectal cancer is unknown.


OBJECTIVE
To examine the association between aspirin use after colorectal cancer diagnosis on colorectal cancer-specific and overall survival.


METHODS
Prospective cohort study of 1279 men and women diagnosed with stage I, II, or III colorectal cancer. Participants were enrolled in 2 nationwide health professional cohorts in 1980 and 1986 prior to diagnosis and followed up through June 1, 2008.


METHODS
Colorectal cancer-specific and overall mortality.


RESULTS
After a median follow-up of 11.8 years, there were 193 total deaths (35%) and 81 colorectal cancer-specific deaths (15%) among 549 participants who regularly used aspirin after colorectal cancer diagnosis, compared with 287 total deaths (39%) and 141 colorectal cancer-specific deaths (19%) among 730 participants who did not use aspirin. Compared with nonusers, participants who regularly used aspirin after diagnosis experienced a multivariate hazard ratio (HR) for colorectal cancer-specific mortality of 0.71 (95% confidence interval [CI], 0.53-0.95) and for overall mortality of 0.79 (95% CI, 0.65-0.97). Among 719 participants who did not use aspirin before diagnosis, aspirin use initiated after diagnosis was associated with a multivariate HR for colorectal cancer-specific mortality of 0.53 (95% CI, 0.33-0.86). Among 459 participants with colorectal cancers that were accessible for immunohistochemical assessment, the effect of aspirin differed significantly according to cyclooxygenase 2 (COX-2) expression (P for interaction = .04). Regular aspirin use after diagnosis was associated with a lower risk of colorectal cancer-specific mortality among participants in whom primary tumors overexpressed COX-2 (multivariate HR, 0.39; 95% CI, 0.20-0.76), whereas aspirin use was not associated with lower risk among those with primary tumors with weak or absent expression (multivariate HR, 1.22; 95% CI, 0.36-4.18).


CONCLUSIONS
Regular aspirin use after the diagnosis of colorectal cancer is associated with lower risk of colorectal cancer-specific and overall mortality, especially among individuals with tumors that overexpress COX-2.
Chan
Andrew T
AT
Gastrointestinal Unit, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, GRJ 722 Boston, MA 02114, USA. achan@partners.org
Ogino
Shuji
S
Fuchs
Charles S
CS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D001241:Aspirin / Q000008:administration & dosage*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011446:Prospective Studies; D012107:Research Design; D011795:Surveys and Questionnaires; D015854:Up-Regulation
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D016861:Cyclooxygenase Inhibitors; D051546:Cyclooxygenase 2; D001241:Aspirin