Good old-fashioned aspirin appears to cut the risk of death in colorectal cancer patients by almost 30 per cent, a study has found.
The research, published in JAMA, the Journal of American Medical Association, is exciting because it appears to show that an inexpensive, commonly used drug can help prevent colon cancer from recurring.
As well as being an effective pain reliever, aspirin is also often recommended for preventing blood clots, heart attacks and strokes. The drug has also been shown in previous research to reduce the risk of colorectal cancer, but it's also known to lead to stomach or intestinal bleeding.
Because of these side effects, long-term aspirin use for the prevention of colon cancer is not recommended. But this new study suggests patients who already have colon cancer may benefit from the little white pills.
Researchers led by Dr. Andrew T. Chan, of Massachusetts General Hospital and Harvard Medical School, looked at nearly 1,300 people with colorectal cancer who'd been followed for an average of 12 years through two large ongoing studies, the Nurses' Health Study and the Health Professionals Follow-up Study. All the patients had had surgery for colon cancer and many also had chemotherapy.
Among the 549 participants who reported that they used aspirin regularly after their diagnosis, 81 died from colorectal cancer (about 15 per cent). In contrast, among the 730 people who didn't use aspirin, 141 died of the disease (about 19 per cent).
Taking into account other cancer risk factors, such as family history, the researchers calculated that those who took aspirin were 29 per cent less likely to die of colorectal cancer and 21 per cent less likely do die overall.
Aspirin seemed to help mostly those patients whose tumours tested positive for COX-2. That appears to make sense, since aspirin has been shown to block COX-2, an enzyme that promotes cell proliferation and allows cancer to spread.
Among those patients known to have a COX-2 positive tumour, the death rate among aspirin takers plunged by 61 per cent. Overall for this group, aspirin reduced death from all causes by 38 per cent.
"These results suggest that aspirin may influence the biology of established colorectal tumors in addition to preventing their occurrence. Our data also highlight the potential for using COX-2 or related markers to tailor aspirin use among patients with newly diagnosed colorectal cancer," the researchers noted.
But they cautioned that it's too early to recommend that all colorectal cancer patients start taking a regular dose of aspirin a few times a week. That because the study was observational, meaning researchers merely observed what patients were already doing, such as taking aspirin regularly for headaches. It's possible that factors other than aspirin accounted for the difference in cancer deaths.
The results need to be confirmed in an experiment where cancer patients would be randomly assigned to take aspirin or placebo. Such a study, based in Singapore, is now underway.
