Aspirin may extend the survival of women in the late stages of ovarian cancer, an Australian study suggests.
A team led by researchers at the QIMR Berghofer Medical Research Institute set out to find what factors could improve survival in women after a diagnosis of the disease.
The study, published in the Journal of the National Cancer Institute, has found the affordable and widely available supermarket drug aspirin is associated with increased survival for ovarian cancer patients by an average of two and a half months.
"It would sound like a small amount of time but for ovarian cancer, when we're talking about survival, an increase of even one week or one month in survival, it's a huge time," study lead author Azam Majidi said.
"Considering the fact that it's a very cheap medication and it's been used in public for years and it's safe ... I think if it really gives improved survival like that, it's a huge discovery."
Ovarian cancer is the sixth-leading cause of cancer-related death in women worldwide.
It is more common with older women and those with a family history of cancer of the reproductive organs.
Symptoms, which can fly under the radar in the cancer's early stages, include bloating, abdominal or pelvic pain, feeling full after eating small amounts and urinary changes, such as having difficulty urinating or needing to urinate urgently.
Less-common symptoms can include bowel changes, weight changes, unexpected vaginal bleeding or pain during sex.
Dr Majidi said unlike other common cancers such as breast or colon cancer, there's no population-based screening test for ovarian cancer.
"It's just an internal organ, ovaries, so most women wouldn't even know that they have a tumour until it's grown to advanced stages and it had emigrated to other organs, and the treatment is just not responsive anymore," she said.
"Around 70 per cent of women, are diagnosed at advanced stages, stage three or stage four when the survival is really low."
From lab to real life
Previous research evaluated how aspirin affects tumour cells, with studies looking at how it can decrease tumour growth and the migration of tumour cells to other organs.
"The reason we started thinking about this and conducting this study was that several laboratory studies had already showed that when they added aspirin to a tumour cell, the growth of tumour was reduced and the reproduction of tumour cells reduced," Dr Majidi said.
She and her colleagues wanted to see if aspirin would work, not at the cell level, but in real patients.
The Ovarian cancer Prognosis And Lifestyle study followed 958 Australian women aged between 21 and 79 with ovarian cancer.
The team gathered information through self-completed questionnaires and classified how frequently participants used non-steroidal anti-inflammatory drugs or NSAIDs (which include ibuprofen, diclofenac and aspirin) during the year pre-diagnosis and post-diagnosis.
The study measured survival from either the start of or 12 months into treatment until the patient died from ovarian cancer or at their five-year follow up.
Researchers observed better survival associated with frequent pre- and post-diagnosis NSAID use, and results were similar for both aspirin and non-aspirin NSAIDs.
Dr Majidi said it was important to note, however, that NSAIDs may not be safe for everyone to take, and suggests people talk to a doctor before using them.
Why aspirin is not a catch-all solution
John Zalcberg, a professor of cancer research at Monash University's School of Public Health and Preventative Medicine, said many observational studies suggest aspirin has a positive impact on the incidence of and survivorship from cancer.
But, he said, it was too soon to say whether NSAIDs like aspirin should be recommended for all cancer patients.
Professor Zalcberg is a member of ASPREE, the Aspirin and Ageing Health Research team led by Monash University. In 2021, he was involved in a study on the effect of aspirin on the incidence of cancer in adults over the age of 65.
The study evaluated 19,000 patients from Australia and the US and, as Professor Zalcberg said, found aspirin may not show a benefit in people with colorectal cancer, or in any other cancer within that age group.
"The incidence was the same, but the death rate was actually even higher," Professor Zalcberg said.
"We don't really have a very good explanation for it.
"What I think it's done is also made us think a bit more carefully around what we should say about aspirin in that sort of [situation]."
Professor Zalcberg said it wasn't the case that people should stop taking aspirin, but in terms of prescribing it for people over 65 "the data is such that we are just not understanding the story fully, and think it's more complicated".
"We'd love to have something that would improve or reduce the incidence [of cancer], perhaps even prevent it, or indeed improve survival," he said.
"That's not clear that we can make those recommendations in a positive way at this point.
"I think the lesson for us is that to make such important recommendations that would treat a whole community ... I think we need probably a bit stronger data than observational data to make that conclusion."
Further tests of aspirin use for ovarian cancer
The next step for Dr Majidi and her colleagues now is to conduct a randomised clinical trial.
"In our study, women were using these medications for a reason," she said.
"For example they had a heart condition, or cardiovascular disease, or some other thing that meant they had to use these medications. That could also affect their overall survival.
"In a randomised trial we would start with women who are not using medications."
Dr Majidi, who hails from Iran, said if her team's observations were confirmed in a randomised trial, it could be significant for people who cannot afford treatment.
"Even though [there has] been advancements in ovarian cancer treatment, most of those new treatments are very expensive and unaffordable ... especially in less affluent countries," she said.
"Since aspirin is just very cheap, and a relatively safe medication compared to other medications, it could be very helpful.
"I think if our results were confirmed by randomised trials, that would be very good finding."