Cancer is one of our scariest diseases. That’s because it is the second leading cause of death in the U.S., killing nearly 600,000 people each year.

It is not surprising that many Americans do everything in their power to avoid exposure to toxins that might increase their chances of getting cancer. Millions have quit smoking. Others buy organic food to reduce exposure to herbicides and pesticides.

Despite such proactive steps, there may be cancer-causing chemicals in one of the least suspected places–medications. Few people realize that many of the medicines they swallow every day may contain compounds that are under a cancer cloud.

The FDA often requires pharmaceutical companies to test their compounds for carcinogenicity in animal models. Not infrequently, medications come back positive for an elevated risk of tumors. That rarely disqualifies them from the drugstore.

Hormone replacement therapy (HRT) is a classic example. Studies have clearly linked estrogen plus progestin with breast cancer (Journal of the National Cancer Institute, online, March 29, 2013). The FDA even has a black box warning about this risk.

Most of the time, however, the FDA doesn’t seem to know what to do about cancer concerns. The popular diabetes drug Actos (pioglitazone) has been banned in France and Germany because of research suggesting an increased risk of bladder cancer. The official U.S. prescribing information describes reports of bladder tumors in rat studies and bladder cancer in humans, but leaves patients and doctors confused about whether the risk is worth worrying about. Other diabetes drugs (Byetta, Januvia, Onglyza and Victoza) have been linked to pancreatitis and pre-cancerous cellular changes in the pancreas.

Sometimes FDA staffers fight amongst themselves about cancer risks. Thomas Marciniak, MD, is a patient safety expert within the FDA. He recently raised a red flag about a potential cancer risk linked to popular blood pressure medications called ARBs (angiotensin receptor blockers). This includes medications such as Benicar (olmesartan), Cozaar (losartan) and Diovan (valsartan).

According to a May 30, 2013 Wall Street Journal  report, Dr. Marciniak sent a message to high-ranking FDA officials stating: “The FDA needs to inform patients and physicians about the ARB lung-cancer risks. The FDA must act now.” A 2011 analysis by the agency reported no increase in cancer. Dr. Marciniak’s boss told the Journal, “We have no reason to tell the public anything new.”

If the FDA cannot agree about drugs and cancer, it is hardly any wonder that physicians and patients get confused. Even when the agency requires cancer warnings, most people don’t know what to make of these cautions.

The popular heartburn medicine omeprazole (Prilosec) carries a notice about abnormal cell growth and stomach tumors (carcinoids) in rats. Does that pose a problem for people?

Dozens of other drugs carry some sort of cancer warning. They include skin creams for eczema (Elidel and Protopic) and powerful bio-tech drugs for rheumatoid arthritis (Cimzia, Enbrel, Humira and Remicade).

When the FDA requires a cancer warning in the prescribing information, it leaves everyone in a quandary. If there is a real hazard, such drugs should be restricted. If the danger is trivial, we should be told the risks are not relevant to people so patients won’t worry needlessly.

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  1. vo

    can’t get a straight answer from doctors, pharmacists, etc. on the dangers of Januvia….alternative medicine offered glyizide…side effect, heart disease..and weight gain. THOSE are real alternatives. HELP

  2. Karen

    >If there is a real hazard, such drugs should be restricted. If the danger is trivial, we should be told the risks are not relevant to people so patients won’t worry needlessly.
    What is “real” and what is “trivial?” These are useless, non-valid words. It is perfectly clear to me that without the medication I take that has a small risk of cancer increase, I won’t live long enough to die of cancer. Perfectly clear. Exquisitely clear. And I “don’t worry,” in part because I philosophically believe all “worry” is “needless.” Act, or don’t act, but don’t worry. Worry probably causes more cancer than all other causes combined, in as much as “worry” is also “inaction.”
    We can still smoke. We can still drink liquor. We can still have unprotected sex, all of which come with an increased risk of cancer that is MUCH Higher than that from most drugs.
    Very few things come with no side effects. All for informing the public, and for letting us make decisions. But removing all risk removes all benefits, too.
    Peoples Pharmacy response: You are quite right that there are new drugs without risks. We still think that he would be better to know more about the risks that exist rather than wonder whether they are significant.

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