Health Briefs

April 19, 2002

ANTI-INFLAMMATORY RXs MAY REDUCE GROWTH OF BREAST CANCER CELLS
I have previously reported on intriguing research that may help to explain why some cancers appear to be less common in people who regularly take certain anti-inflammatory medications (e.g., aspirin, ibuprofen, naproxen, Vioxx, Celebrex, etc.).

In the current issue of the journal Cancer Research, new research shows that the growth of at least some types of breast cancer cells can be inhibited by exposure to Celebrex and related anti-inflammatory drugs. These drugs inhibit a class of enzymes referred to as COX enzymes (cyclooxygenase).

When exposed to Celebrex in this study, breast cancer cells that normally produce COX not only grew at a significantly slower rate, but when implanted into mice, Celebrex appeared to also significantly reduce the number of these tumor cells that spread to distant sites (metastasized).

Several different types of cancers have already been shown to synthesize COX enzymes, including many breast, prostate and colorectal cancers. However, it is currently unknown whether all-or even most-types of cancer are responsive to these drugs, although a great deal of research is currently underway to answer this question (there are already several research studies that have shown an apparent reduction in the risk of developing colon polyps in people who take anti-inflammatory COX-inhibitors).

This is a very exciting area of cancer research, as there are many anti-inflammatory drugs already approved for human use. Of course, all of these medications can have potentially serious side effects, and none of them are approved as "anti-cancer" drugs at this time. However, I predict that this area of cancer research is going to produce some significant breakthroughs in terms of cancer prevention and, possibly, cancer treatment.

CHANGE YOUR SEX BY DRINKING WATER?
From the Proceedings of the National Academy of Science (PNAS) comes a rather disturbing finding. Biologists have been studying an apparently rising incidence of deformities in frogs throughout the United States over the past decade or so. Missing or deformed limbs and abnormal sex organs are two of the most commonly seen deformities in these amphibians.

The study in PNAS exposed African clawed frogs to a pesticide called atrazine, which is in widespread use throughout the US. Indeed, so prevalent is atrazine in the water supply, the FDA sets allowable concentration limits for its presence in public drinking water.

After exposing frog larvae in the laboratory to concentrations of atrazine that were comparable to levels measured in the wild, the University of California (Berkeley) researchers found that male frogs became "demasculinized."

Worse still, many of the frogs went on to develop microscopic evidence of hermaphroditism (the presence of sexual organs from both sexes in one individual). A ten-fold decrease in testosterone levels was also noted in the male frogs exposed to atrazine.

Scientists around the world have previously linked, at least theoretically, the observed decline in human sperm counts with the pervasive presence of certain pesticides in the environment. Many of these compounds are so chemically stable that it may take many decades for them to be broken down into less toxic substance. While humans may or may not react to atrazine in the same manner as amphibians, the results of this study are nonetheless worrisome, as frogs and humans share amazing similarities when it comes to reproductive physiology.

RADIATION TREATMENT REDUCES REPEAT NARROWING OF BYPASS GRAFTS
In coronary artery bypass patients who must subsequently undergo angioplasty and placement of coronary artery stents (tiny expandable tubes that help to keep the narrowed coronary artery open) because the arterial bypass graft has become narrowed, repeated episodes of graft artery narrowing can occur at the site of the stent. When this occurs, the angioplasty must be repeated (using a tiny inflatable sausage-shaped balloon) to allow blood to flow through the artery, and to the heart muscle, once again. Drugs and radiation treatment are, therefore, routinely used to reduce the risk of restenosis, or narrowing, in bypass grafts taken from the arteries (internal mammary arteries) that run alongside the breastbone (sternum). However, the effectiveness of radiation treatments to heart bypass grafts taken from leg veins has not been well studied. In almost all patients who require multiple coronary artery bypasses, at least some of the bypass grafts are created using the greater saphenous vein(s) from one or both legs.

In this week's New England Journal of Medicine is a report on the use of radiation treatment following restenosis of previously stented saphenous vein bypass grafts. These study patients had all undergone coronary artery bypass with saphenous veins, and had subsequently required angioplasty and stenting of these vein grafts due to stenosis. When the patients presented again with recurrent stenosis in the stented segment of the bypass grafts, they were treated, once again, with angioplasty.

A total of 60 patients then underwent radiation treatment of the reopened vein bypass grafts and 60 patients received only a "placebo treatment" (no radiation). The restenosis rate in the irradiated group of patients was 21% after six months of observation, as compared to a 44% restenosis rate in the placebo group. Likewise, at 12 months, the irradiated group had required significantly fewer (17% versus 57%) additional procedures to reopen a clogged bypass graft than did the placebo group. Finally, 32% of the irradiated group experienced a recurrent heart attack or death due to heart attack, while 63% of the placebo group experienced such adverse events after 12 months of observation.

Bottom line: in coronary artery bypass patients who have required angioplasty and stenting of saphenous vein bypass grafts because of bypass graft stenosis, irradiation of the stented grafts should probably be considered.

Dr. Robert A. Wascher