Aspirin tied to higher risk of advanced cancer diagnosis and mortality

Reuters Health - 18/09/2020 - Older adults who take daily low-dose aspirin may be more likely than those who don't to be diagnosed with advanced cancers and to die from these malignancies, a randomized trial suggests.

Researchers randomly assigned 19,114 community-dwelling adults 70 years and older in the U.S. and Australia 1:1 to take 100mg of aspirin or a placebo daily. Cancer history wasn't part of the exclusion criteria (19% of participants had a prior cancer diagnosis) but participants had to be healthy with a life expectancy of at least another five years and no diagnosis of cardiovascular disease, dementia, or physical disability.

After a median follow-up of 4.7 years, there were 981 cancer events in the aspirin group and 952 in the placebo group and no statistically significant difference in all-cancer incidence between groups.

But compared with the placebo group, participants in the aspirin group were more likely to be diagnosed with cancer that had metastasized (HR 1.19) or was at stage 4 at the time of diagnosis (HR 1.22). And people randomized to aspirin therapy were also more likely to die when they had cancers that presented at stage 3 (HR 2.11) or stage 4 (HR 1.31).

These results suggest that it may not make sense to initiate aspirin therapy in elderly adults as a cancer prevention measure, said Dr. John Burn, a professor of clinical genetics at Newcastle University in the UK who wasn't involved in the study.

"In terms of cancer prevention, it's probably helpful for people already on aspirin to continue into their 70s but not if they are starting at that age," Dr. Burn said by email.

During the study period, a total of 1,933 participants (10.1%) were diagnosed with new incident cancers. Out of this group, a total of 1,270 (65.7%) had localized cancer, while 363 (18.8%) had new metastatic cancers, and 113 (5.8%) had metastatic disease related to a cancer diagnosed prior to the start of the study.

Among those diagnosed with cancer during the study, 495 (25.6%) died from malignancies, including 52 fatalities due to the progression of cancer diagnosed before the start of the study.

While the current analysis wasn't designed to determine why aspirin might impact cancer incidence or outcomes, it's possible that by reducing inflammation aspirin prevents new cancers from developing but also allows well-developed cancers to spread, Dr. Burn said.

There was no significant difference between the aspirin group and the placebo group in the incidence of hematological tumors or solid cancers, even by specific tumor type, researchers report in the Journal of the National Cancer Institute.

One limitation of the study is that it was underpowered to examine the impact of aspirin on specific subgroups or cancer subtypes, the study team notes.

Lead study author Dr. John McNeil of the Peter MacCallum Cancer Centre in Melbourne, Australia, did not respond to emails seeking comment.

Some effects of aspirin therapy on cancer incidence or mortality might also take longer to become apparent, said Tim Bishop, a professor of genetic epidemiology at the University of Leeds in the UK, who wasn't involved in the study.

"The study has only been going for five years so this is comparatively short term," Bishop said by email. "We will have to wait longer to see if this effect remains."

By Lisa Rapaport

SOURCE: https://bit.ly/2ZQ1Edv Journal of the National Cancer Institute, online August 11, 2020.



Posted on 18 September 202030 September 2020