Jan. 15 (UPI) -- People who take aspirin at least three times per week are more likely to survive bladder cancer, according to an analysis published Friday by JAMA Network Open.
Regular aspirin use also was associated with a reduced risk for death from breast cancer, the data showed.
However, taking aspirin had no effect on a person's risk for getting several forms of the disease, including bladder, breast, gastrointestinal or pancreatic cancers, the researchers said.
Aspirin also did not reduce a person's risk for death from gastrointestinal or pancreatic cancer, they said.
"Although aspirin use at least three times per week was associated with the strongest risk reduction, any aspirin use was associated with increased bladder and breast cancer survival," researchers from the National Cancer Institute wrote.
"These results may indicate that for some cancer types, any aspirin use may be advantageous [but] greater benefit may be observed with increased frequency of use," they said.
The findings are based on an analysis of cancer diagnoses and survival among nearly 140,000 participants in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, an ongoing National Cancer Institute-led research initiative intended to track the prevalence of these diseases.
For this study, the researchers focused specifically on rates of these cancers and deaths from the disease among participants age 65 and older, 18% of whom reported taking aspirin at least three times per week.
Among the study participants, just over 1% were diagnosed with bladder cancer and 3.3% were diagnosed with breast cancer, the data showed.
Cancers of the gastrointestinal, or GI, tract, the esophagus or the pancreas as well as uterine cancer were less common, though collectively they were diagnosed in 1.6% of the study participants, the researchers said.
Participants who used aspirin three or more times per week were more likely to survive for up to 20 years after being diagnosed with either bladder or breast cancer than those who took the over-the-counter drug less, according to the researchers.
However, the benefits of aspirin in survival decline over time, and the drug did not have the same effect on survival with the other cancers included in the study, they said.
Aspirin blocks the body's production of COX-2, an enzyme that may play a role in the progression of bladder and breast cancers, the researchers said.
Daily use of the drug has been recommended for older adults for years, as its role as a blood-thinner also helps reduce heart attack risk.
However, its use has been associated with the development of stomach ulcers in some people.
"Although aspirin use may confer a cancer protective effect, it remains necessary to consider the harms, as well as the benefits, of long-term aspirin use," the researchers wrote.