Copenhagen, Denmark—Recent research raised hopes that low-dose aspirin use might improve survival in prostate-cancer patients.

Results of a new study published in Annals of Internal Medicine did not find that to be the case. The results did suggest, however, that while low-dose aspirin use does not seem to reduce the overall risk for prostate cancer death at the population level, use of the common blood thinner/painkiller might be inversely associated with prostate cancer mortality after 5 years from cancer diagnosis.

Researchers from the Danish Cancer Society Research Center, Aarhus University Hospital, Copenhagen University Hospital, and University of Southern Denmark used nationwide Danish registries to determine the association between postdiagnosis use of low-dose aspirin and prostate cancer mortality.

Included in the study were more than 29,000 men, median age 70, with incident prostate adenocarcinoma between 2000 and 2011. Researchers gathered data on tumor characteristics, drug use, primary prostate cancer therapy, comorbidity, and socioeconomic parameters.

Postdiagnosis use of low-dose aspirin (75 mg to 150 mg) was defined as two or more prescriptions filled within 1 year after prostate cancer diagnosis, with follow-up beginning a year after prostate cancer diagnosis. For the secondary analysis, low-dose aspirin use was assessed within exposure periods of 5 or 7.5 years after prostate cancer diagnosis.

During a median follow-up of 4.9 years (interquartile range, 3.1 to 7.2 years), through 2015, 7,633 of the men died of prostate cancer and 5,575 died of other causes.

Researchers determined that postdiagnosis low-dose aspirin use was associated with adjusted hazard ratios (HRs) of 0.95 (95% CI, 0.89-1.01) for prostate cancer–specific mortality and 1.12 (CI, 1.05-1.20) for other-cause mortality. On the other hand, the secondary analyses showed that prostate cancer mortality was slightly reduced with low-dose aspirin use after the 5-year (HR, 0.91 [CI, 0.83 to 1.01]) and 7.5-year (HR, 0.84 [CI, 0.72 to 0.97]) postdiagnosis exposure periods, “notably among patients filling prescriptions for a large quantity of low-dose aspirin tablets during the 7.5-year period,” according to the study team.

A limitation of the study was that data on OTC aspirin use were unavailable.
“The study did not support an overall effect of postdiagnosis low-dose aspirin use on prostate cancer mortality. However, results for extended exposure periods suggest that low-dose aspirin use might be inversely associated with prostate cancer mortality after 5 years from cancer diagnosis,” the study authors conclude.

Patients benefiting most were those with low Gleason scores, meaning that their prostate cancer was unlikely to progress, and those who took low-dose aspirin for an extended period of time, according to the report.

 « Click here to return to Weekly News Update.