Mechanism speculation focuses on COX-2 pathway
Theories of the mechanisms behind a potential benefit of aspirin for those with bladder cancer include that urothelial cancer has increased RNA and protein expression of cyclooxygenase-2 (COX-2) and urinary prostaglandin E2, “suggesting up-regulation of the COX-2 pathway during cancer progression,” the authors wrote.
In breast cancer, a similar elevated expression of COX-2 has been shown to predict disease outcomes, including progression and decreased survival.
“This may be partly due to the mechanistic interplay between angiogenesis, cell proliferation, apoptosis, and inflammatory processes,” the authors noted.
The study isn’t the first to show a benefit specifically with bladder cancer; other studies include recent research (J Urol. 2018 Nov;200[5]:1014-21) showing that daily aspirin use among patients with bladder cancer was associated with increased 5-year survival following radical cystectomy, the authors noted.
Dr. McNeil noted that the new findings from the U.S. researchers, particularly regarding bladder cancer, are of interest. “The reduction in mortality from breast cancer is modest, but the reduction in mortality from bladder cancer was more impressive,” he said.
“However, given the fact that this finding is observational data and was a sole finding among multiple comparisons, it must be seen as suggestive rather than proven.”
Regarding possible mechanisms, Dr. McNeil added that, like the bulk of the prior research, many questions remain.
“There have been many suggestions about ways that aspirin might work at a molecular and cellular level, but no firm consensus has been reached.”
The study authors and Dr. McNeil disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.