New large-scale studies published on Thursday in the journal JAMA Oncology have suggested that a daily low dose of aspirin could help reduce the risk of certain cancers.

The first of the two studies, led by Harvard T.H. Chan School of Public Health, USA, along with colleagues from Brigham and Women’s Hospital in Boston and Moffitt Cancer Center in Tampa, found that regular use of low-dose aspirin (100 milligrams or less) may lower the risk of ovarian cancer, the fifth most common cause of cancer-related death among US women.

The researchers analyzed data on 205,498 women, looking at the women’s use of aspirin, low-dose aspirin, non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs), and acetaminophen, including the number of tablets used, and the frequency, timing, and duration of use.

They found that women who reported recent, regular use of low dose aspirin had a 23 percent lower risk of developing ovarian cancer when compared with women who did not regularly take aspirin.

However, taking a low dose of aspirin over a longer period of time did not appear to result in any further decrease in the risk of ovarian cancer.

Standard-dose aspirin (325 milligrams) use was also not associated with a lower risk.

The researchers also found that the use of non-aspirin NSAIDs, such as ibuprofen and naproxen, appeared to be linked with an increased risk of ovarian cancer when taken in quantities of at least 10 tablets per week over a period of many years, although they noted that this finding needs to be confirmed in further studies.

The second study, led by Massachusetts General Hospital (MGH), analyzed data from more than 133,300 participants, finding that regular aspirin use may reduce the risk of developing primary liver cancer — also called hepatocellular carcinoma (HCC) — which is the second leading cause of cancer death worldwide.

The results showed that those who regularly use aspirin, defined as two or more standard-dose tablets a week, had a 49 percent reduction in the risk of developing HCC compared to those who never used aspirin or used it infrequently.

For participants who had been taking aspirin for five years or more, the risk was reduced even further, by 59 percent. However, this reduction in risk decreased if participants stopped taking aspirin, and disappeared altogether after eight years if aspirin use was stopped.

Regular use of acetaminophen or NSAIDs like ibuprofen had no impact on HCC risk.

Aspirin is known to block the production of inflammatory lipids that can lead to liver injury, and while some previous studies have suggested that regular use could help prevent HCC, information on the optimal dosage and required duration of treatment has not been available.

Both of the studies suggest that aspirin may reduce the risk of breast and liver cancer by reducing inflammation in the body, although both teams of researchers added that more research is needed to better understand the relationships between aspirin and cancer.