Does insulin cause cancer, and should you stop taking Lantus?

The potential link between a specific form of long-acting insulin, known as insulin glargine and branded as Lantus, and cancer, could be gaining momentum.

First off, let me say that both human and porcine insulin are safe, and have no association with cancer. The report specifically relates only to a synthetic, long acting form of insulin.

Does insulin cause cancer, and should you stop taking Lantus? According to a series of retrospective studies from Europe, “301,136 insulin-treated patients in Germany, Sweden and Britain suggest Lantus may increase the risk of cancer . . . particularly breast cancer.” It should be noted that the data from these type of studies is not strong, and nowhere near the standard of a randomized, controlled trial, where the effects of one drug is compared to a placebo.

Also, the apparent absolute risk is small, with the largest study finding, “a difference of roughly one extra cancer diagnosed for every 100 people taking Lantus compared with those on human insulin.”

Right now, it’s really too early to make any recommendations, and the American Diabetes Association warns against modifying treatment regiments based on data that were “conflicting and inconclusive.” More research, specifically a prospective randomized trial, needs to be done.

Leading diabetes patient blogger Amy Tenerich predicts the news “kicks off just the kind of anti-Avandia media frenzy that frightens patients off their medications, without real substantiation of the potential danger.”

Matthew Mintz, an internist who frequently writes about diabetes medications, also calls for patients not to immediately stop their Lantus, and instead, consider other injection options, such as Byetta.

Time will tell whether a potential uproar is brewing. Sanofi-Aventis, the makers of Lantus, has a lot riding on the drug, which is projected to contribute 4 to 5 billion dollars in revenue. I’m sure they’re nervously watching the impact of these studies very closely.

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  • LynnB

    Because insulin is a growth factor I do find it somewhat plausible that a very long acting insulin could in some indirect way allow or cause cancer cells to grow. High blood sugars can cause problems much more rapidly with a very high probability so I’m not about to give up on long-acting insulin.

    I would doubt that this problem , if it exists is unique to Lantus. Unfortunately there is no disinterested agency which will see if Levemir has the same problem or perhaps there is even an increased incidence of tumors with high doses of NPH insulin. The only group that will fund research is likely to be a pharmaceutical company and there is nothing in it for them so we may never know the answer.

    I get especially worried because many of my colleagues in obstetrics and gynecology are using this in pregnancy even though there is no data to support it and is not FDA approved.

  • Christine

    I find the recommendation to try Byetta instead of Lantus kind of odd, since Lantus is commonly used by type 1 diabetics, and Byetta is a type 2 med.

    Lynn, I’m GLAD Lantus is used in pregnancy. It’s known to be far better at controlling glucoses than NPH. There’s a weak link to Lantus and cancer. There’s a strong link to better glucose control and healthier pregnancies.

  • Jerry Everetts

    Man, I have been using Lantus for over a year now, and a lot of it too. This type of news makes me very nervous. I always worry that maybe some drug companies are keeping these kind of things on the hush hush to protect profits.

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