Is “Never Recommend A Carcinogen” An Appropriate Policy? Apparently Only For Tobacco

The Wall Street Journal’s “Numbers Guy” Carl Bialik blogged in April on the scientific debate about promoting smokeless tobacco as a substitute for cigarettes (read it here). Bialik’s well-balanced article included expert comments on the science of tobacco harm reduction, in addition to quotes from the usual array of individuals and organizations opposed to offering smokers safer options.

On re-reading Bialik’s article, I was struck by one passage in particular:

“‘We wouldn’t recommend anybody using a product that causes cancer,’ said Cathy Backinger, chief of the tobacco control research branch at the National Cancer Institute.”

At first glance, the comment sounds perfectly reasonable. Surely no one at the NCI would recommend that ANYBODY use a product that causes cancer. Well, it turns out that this is completely false. In fact, the NCI recommends routinely that women take a medication that is known to cause two forms of cancer.

The medication is tamoxifen, which, according to an NCI website (available here), “interferes with the activity of estrogen, a female hormone that can promote the development of cancer in the breast.” The NCI states that “Tamoxifen is approved by the U.S. Food and Drug Administration (FDA) for the prevention of breast cancer and for the treatment of breast cancer, as well as other types of cancer.”

In other words, the NCI endorses the use of tamoxifen by women who don’t have breast cancer but who are at risk of developing it.

But there’s a problem. The NCI acknowledges that “Tamoxifen increases the risk of two types of cancer that can develop in the uterus: endometrial cancer, which arises in the lining of the uterus, and uterine sarcoma, which arises in the muscular wall of the uterus.” The NCI says tamoxifen doubles the risk for endometrial cancer; the magnitude of the sarcoma risk is not specified. The NCI also cautions that “women who took tamoxifen had an increased chance of developing blood clots and an increased chance of stroke.”

The NCI justifies the use of tamoxifen with a straightforward rationale: “The benefits of tamoxifen as a treatment for breast cancer are firmly established and far outweigh the potential risks. Patients who are concerned about the risks and benefits of tamoxifen or any other medications are encouraged to discuss these concerns with their doctor.”

There are legitimate reasons to recommend tamoxifen for women who are at risk for developing breast cancer. Similarly, there is a rock-solid scientific and medical foundation for recommending smokeless tobacco – with cancer risks that are barely measureable by modern epidemiologic methods – to smokers who otherwise face far higher risks of developing a plethora of medical illnesses.

If the Backinger principle was adopted by physicians, they would withhold tamoxifen from women at risk for breast cancer on the grounds that it may cause cancer of the uterus. That application would violate principles of public health and condemn thousands of women to a life with – and perhaps death from – breast cancer. Dr. Backinger’s refusal to consider tobacco harm reduction similarly violates public health principles and condemns millions of inveterate smokers to a disease and death.

Public health policies should be consistent in using scientific evidence of relative risk to promote legitimate life-saving strategies.