Aspirin for Cancer Prevention

Aspirin For Cancer? Could Be!

by Laura Dolson

Who'd have thought it? Those little white pills in most of our medicine cabinets could hold a key to what is called "chemoprevention" - using medications to prevent cancer. Aspirin use has been linked to a reduction in risk in colon, bladder, and prostate cancer, among others. This most recent study to catch interest was presented at the annual meeting of the Society of Gynecologic Oncologists, looking at aspirin use and ovarian cancer. What exactly was the study, and what did it show and not show? If aspirin does prevent cancer, how does it work? What might this mean for women who already have cancer? Let's take a look at the study, and what else is known about aspirin and similar drugs.

Capsule Summary: This study showed that taking aspirin three times per week for 6 months or more reduced the rate of ovarian cancer by 40%. Don't run out and start yourself on aspirin, though. For more information, read on. Page One (below) has the details of the study, and Page Two explains how aspirin may work against cancer, the problems with aspirin, and what's next in this area.

The Study - This particular study gathered data from an ongoing study called the NYU Women's Health study, which was originally designed to help understand the effects of female hormones on cancer risk. The women entered the study between 1985 and 1991, and answer questionnaires every two years. The aspirin study focused on questionnaires sent out in the mid-90's which included questions about aspirin usage, and what happened to those women afterwards vis a vis ovarian cancer, looking only at women who were diagnosed more than a year after the questionnaire.

The Numbers - Out of 14,275 women in the large study, 140 were diagnosed with ovarian cancer over the 12 year period. Of these, 68 qualified for the aspirin study, mainly according to when they were diagnosed and the type of cancer (epithelial ovarian cancer is the most common type, and the type being studied). They took each of these women and matched them on several characteristics with 10 women from the study who didn't get cancer and looked at the differences in aspirin use between the groups. It turned out that out of the 68 women with cancer, 7 (10%) had taken aspirin at least 3 times per week for a period of 6 months or longer. Of the women who didn't have cancer, 16% had taken aspirin for this amount of time. This means the aspirin-taking women in this study had a 40% reduction in their risk of getting ovarian cancer.

Is this a good study? - One of the good things about the study is that it is prospective, meaning that the questions about aspirin were answered before the women were diagnosed with cancer. This is preferable to a retrospective study, where the participants are asked to remember what they did years before. There have been retrospective studies about aspirin and ovarian cancer in the past, but this is probably the first prospective one. Because of this, the data are more reliable.

However, the study stops short of being a randomized study, or experiment, which would be much more powerful. In doing an experiment, two groups of women would be randomly assigned to either take aspirin or not and then followed to see who got cancer. In this study, there was no random assignment - the women who were taking aspirin were doing it for some other reason, which may influence other things in their bodies, including cancer. Another weakness of the study is the low numbers. Fewer participants in the study mean the results can't be generalized as well to the population at large. Also, the amount of aspirin used by the participants was not taken into account. We only know that it was at least three times per week for at least six months.

Other research about aspirin and cancer - The potential anti-cancer effects of aspirin and other NSAIDS (nonsteroidal anti-inflammatory drugs, including ibuprofen) have been studied most carefully in regards to colon cancer, where many studies have shown a protective effect. The mechanisms have also been observed in the most detail in regards to colon cancer, and most of the theories about how aspirin might work have come from that research. There have been at least three other (retrospective studies) with aspirin or other NSAIDS and ovarian cancer which have shown a correlation with reduced risk. In addition, animal and human research has shown some chemopreventative effects in cancers of the bladder, cervix, prostate, breast, and lung, among others.

Page 2> How Aspirin Might Work, plus The Down Side

The material on this page and Web site is for informational and educational purposes only, and should not substitute for medical advice. Anyone having questions about the application of information appearing here to a specific person or situation should obtain advice from a qualified physician.