Aspirin, Tylenol And Motrin Could Cut Breast Cancer Risk

By Margarita Nahapetyan

Aspirin and other painkillers, such as Tylenol, Aleve, Motrin and Advil, which cause a reduction in the levels of estrogen in the body, can cut a woman's risk of developing breast cancer, US biomedical scientists have found.

Postmenopausal women in the study who took aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) on a regular basis, had lower estrogen levels in their bodies when compared to their counterparts who did not take pain relief medications. Study principal author Margaret A. Gates, ScD, a research fellow in epidemiology at Boston's Brigham and Women's Hospital and Harvard Medical School, said that this association must still be confirmed before analgesics are recommended for the prevention of breast cancer. This is because in some cases, the risks associated with these drugs may outweigh their potential benefits. For example, the use of aspirin and NSAID on a regular basis are linked to rare, but quite serious stomach and intestinal bleeding, and Tylenol has been associated with liver failure.

In their new study, Dr. Gates and her fellow colleagues analyzed data on women who took part in the Nurses' Health Study, which involved more than 120,000 female nurses, between the ages of 30 and 55, in 1976. All women were asked to fill out lifestyle and medical history questionnaires at the onset of the study, and every two years afterward. In 1989-1990, a subset of 32,826 participants also gave a blood test and were asked about their menopausal status.

From this subset, Dr. Gates and her team selected 740 women with an average age of 61 years, who had not used hormone therapy in the previous 3 months, reported having no history of cancer and had written about their use of pain relief medications in the most recent questionnaire (1988 or 1990). The experts analyzed the women's use of aspirin, NSAID and acetaminophen and blood samples were used to measure levels of hormones.

The association between painkiller-use and hormone levels was being examined after adjusting for a variety of possible factors, such as menstrual and obstetric history, smoking and alcohol, exercise, body mass index, age at the time of giving a blood sample and time of the day the sample was taken.

Of the 740 women examined, 31 per cent were regular users of aspirin, 19 per cent were regular users of non-steroidal anti-inflammatory drugs and 17 per cent were regular users of paracetamol. Researchers found that women who reported using the over-the-counter pain relief drugs at least 15 days every month had estrogen levels that were between 13 and 15 per cent lower when compared to women who reported no use of painkillers.

Exactly why painkillers decrease levels of estrogen in the body is not clear yet. But, according to Dr. Gates, one hypothesis is that the analgesics may prevent the expression of an enzyme, aromatase, that converts testosterone to a form of estrogen in the body. Gates said that the relationship between lower estrogen levels and a lower risk of developing breast cancer is "very strong" and noted that the association between lower levels of estrogen and development of ovarian cancer is "also there."

The results of the study appear in Cancer Epidemiology, Biomarkers and Prevention, a journal of the American Association for Cancer Research.