Sunday, December 26, 2010

Gardasil Vaccine Prevents Anal Cancer

As physicians, we weigh the pros & cons of each therapeutic option with our patients daily.  What may be of benefit to one individual may be too dangerous for another to undertake.  I wish it were that simple but too often, emotions complicate our logic & science.  How else do you explain the 3,000-49,000 patients who refuse their yearly influenza vaccination and then end up paying the price of hospitalization & death for their illness (new reporting standards from the CDC this year).  Let's not forget the $10 billion in lost productivity and direct medical expenses and another $16 billion in lost potential earnings as a result of this preventable illness.

More recently, there has been a tremendous backlash against the use of Gardasil to prevent human papilloma virus (HPV) infections, first in women, and now in men.  Why the hesistance?  After all, multiple studies demonstrate that when administered properly, Gardasil can prevent cervical, vulvar & vaginal cancer in women, and genital warts in both men & women, all due to HPV.  Perhaps because HPV is considered a sexually transmitted illness and a vaccination against a sexually transmitted illness could be considered an e-ticket to have sex & promiscuity.  Of course it doesn't help that the vaccine is not inexpensive and that most insurance companies don't cover it.  But we're talking about preventing cancer, folks!

So in a gesture of holiday largess, the FDA just announced the approval of Gardasil for the prevention of anal cancer due to HPV types 6, 11, 16 & 18, to be administered to men & women 9-26yo (same age group as for the other above mentioned indications).  While anal cancer is not common, its incidence is increasing with the American Cancer Society estimating that 5,300 persons will be diagnosed in the coming year.  In the study used to substantiate Merck's request for another indication for their vaccine, Gardasil was shown to decrease the risk of anal cancer by 78%.

I don't know about you, but I look at this 78% reduction in cancer risk and its attendant surgery, radiation, & chemotherapy treatment and complications as being worth the relative cost of Gardasil and the risk of vaccine related side effects, such as fainting, pain at the injection site, headache, nausea, and fever.  Bottom line, for my kids, Gardasil is an ounce of prevention worth the proverbial pound of cure.

PS Don't be surprised if Gardasil receives an indication in the future to prevent HPV-related oral cancers given our society's generalized increased acceptance of oral sex.

2 comments:

  1. Nice summary. But to make the statistics more meaningful, it would be useful to see a number-needed-to-treat. In other words, statistically, how many people need to be vaccinated to prevent one case of anal cancer? In the Merck study, the 78% reduction was seen in the highest-risk population - MSM (men-who-have-sex-with-men). Isn't it a leap to suggest that the same reduction would be seen in people of average risk? The Merck study also used anal-intraepithelial neoplasia (AIN) as its endpoint. AIN is not the same as cancer. It's a pre-cancer and, if it is similar to cervical-intraepithelial neoplasia (CIN) - it's probably fair to assume that many cases will spontaneously regress without any treatment. While I think the cervical cancer prevention effects of HPV vaccination are very worthwhile, I will await more data before recommending the vaccine for the purpose of prevention of anal cancer in groups other than those studied (MSM).

    ReplyDelete
  2. As expected from the man behind the superlative medical reference tomes at www.meistermed.com, Dr. Schechtman's points are all well taken. In fact, similar to looking at all-cause mortality as the gold standard outcome, number-needed-to-treat (NNT or the reciprocal of the absolute risk reduction) rather than the relative risk reduction that I quoted above is really the gold standard by which one should determine value (in the appropriate population).

    ReplyDelete