Aspirin Tied To Improved Breast, Bladder Cancer Survival In Older Adults

Older adults who take aspirin may be more likely than those who don't to survive breast or bladder cancer, a new study suggests.

Researchers examined data on 139,896 people 65 years and older who enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and had no history of cancer at baseline (1993-2001). Participants were initially followed for 13 years or through 2009, whichever came first; researchers also collected cancer incidence data through 2014 and mortality data through 2015.

During follow-up, a total of 32,580 cancers were reported, including 1,751 (5.4%) bladder cancers, 4,552 (14%) breast cancers, 332 (1%) esophageal cancers, 397 (1.2%) gastric cancers, 878 (2.7%) pancreatic cancers, and 716 (2.2%) uterine cancers.

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Aspirin use did not appear to significantly influence the incidence cancers studied.

However, any aspirin use was associated with lower mortality for bladder cancer (hazard ratio 0.75) and breast cancer (HR 0.79). Taking aspirin at least three times weekly was associated with even lower mortality risk for bladder (HR 0.67) and breast (HR 0.75) malignancies.

This suggests that aspirin may improve survival outcomes for patients with breast and bladder cancers, the study team concludes in JAMA Network Open. However, more research is still needed, said lead study author Dr. Holli Loomans-Kropp, of the Division of Cancer Prevention at the National Cancer Institute in Rockville, Maryland.

"In this study, we didn't investigate the mechanism of action for aspirin in any of the evaluated cancers, so I do not have the appropriate data to suggest why aspirin is associated with or not associated with certain cancers," Dr. Loomans-Kropp said by email.

Because the study was a secondary analysis of a randomized trial, the results also don't provide data to help inform clinical practice, Dr. Loomans-Kropp said.

Several cancers in the study that didn't appear to be significantly impacted by aspirin in the study have been previously found to be unresponsive to aspirin, said Lenard Lichtenberger, a professor emeritus at the University of Texas Health Sciences Center at Houston who wasn't involved in the study.

"The relationship between aspirin consumption and cancer incidence, progression and mortality has been the focus of numerous pre-clinical and clinical studies, with the preponderance of studies demonstrating one of the world oldest drugs has significant anti-cancer activity," Lichtenberger said by email.

Aspirin's anti-platelet properties may impact the development and outcomes from certain cancers more effectively when it's taken daily, Lichtenberger said. Including people who used aspirin only three days a week in the same group as daily users in the current analysis may have made the drug appear less beneficial, he said.

"If the drug is not taken daily at an anti-platelet dose of at least 81 mg/day, one runs the risk of platelets rebounding thereby nullifying any benefit aspirin may have," Lichtenberger said.

—Lisa Rapaport

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