Low Dose Aspirin Could Increase Mesothelioma Risk

If you are at risk for malignant mesothelioma, you may want to think twice about taking low dose aspirin on a regular basis. 

A new study suggests that low dose aspirin could speed up the growth and spread of cancer cells in older people. 

The study appears in the Journal of the National Cancer Institute. It involved more than 19,000 people in Australia and the US. 

Low Dose Aspirin and Mesothelioma

Many older people take small daily doses of aspirin to reduce their risk for heart attack. Aspirin reduces inflammation and the blood’s ability to clot. This makes it less likely to form the blockages that cause heart attacks and strokes. 

But mounting evidence suggests that taking low dose aspirin could do more harm than good. 

It may be especially dangerous for people who have lived or worked around asbestos. Asbestos is the primary cause of mesothelioma. Anyone who has been exposed to asbestos is at risk for mesothelioma. 

It can take years to develop. During this time, a person may have no symptoms. But once it shows up, mesothelioma moves quickly. Pleural mesothelioma is one of the most aggressive types of cancer. 

The findings of the new study suggest that low dose aspirin could add fuel to that fire. 

Drug Raises Risk for Aggression and Spread

More than 19,000 people over 70 were part of the study. Researchers divided them into two groups. One group included people who took a daily dose of aspirin. The other group did not take aspirin. 

There was no difference in the rate of mesothelioma or any other cancer among the two groups. Both groups had about 950 cancer cases. But people in the low dose aspirin group were twice as likely to die of stage 3 cancer. The same group also faced a 20 percent higher risk that their cancer would spread. 

“These findings suggest that in older persons, aspirin may accelerate the progression of cancer and thus, suggest caution with its use in this age group,” writes lead author John McNeil, MBBS, MSc, PhD, of the Peter MacCallum Cancer Centre in Melbourne, Australia.

Confusion Over Aspirin Safety

The new study comes just a year after two other studies seemed to draw the opposite conclusion about low dose aspirin. 

One of those studies focused on non-small cell lung cancer (NSCLC). NSCLC is similar to pleural mesothelioma in many ways. 

In the lung cancer study, 164 patients with early-stage NSCLC had stereotactic body radiotherapy (SBRT). The patients who took low dose aspirin lived nearly five months longer than those who did not. At two years, 57 percent of the aspirin group was still living versus 48 percent of the non-aspirin patients. 

That study did not separate people by age like the new study does. This is important for people at risk for mesothelioma. Most people diagnosed with mesothelioma are over 65. 

Sources: 

McNeil, John, et al, “Effect of aspirin on cancer incidence and mortality in older adults”, August 11, 2020, Journal of the National Cancer Institute, Epub ahead of print, https://academic.oup.com/jnci/advance-article/doi/10.1093/jnci/djaa114/5889955

Hermann, G, et al, “Concurrent Aspirin Use Is Associated with a Trend in Improved Overall Survival in Early Stage Lung Cancer Patients Undergoing SBRT: A Retrospective Review”, September 15, 2019. ASTRO Presentation