Saturday, March 22, 2008

HPV, STIs, and Teenaged Girls: What does 1 in 4 mean and what can be done?

Several of my recent blog postings have dealt with viruses that cause cancer. One cancer-causing virus that has been in the news lately is human papillomavirus (HPV), a sexually transmitted virus that can cause cervical cancer. The development of a vaccine that protects women from the specific HPV strains that cause cervical cancer was a major step forward in cancer prevention.

Although it is clear that the vaccine reduces infections with these HPV strains, because of the long time interval between infection and the development of cancer it has not yet been proven that vaccination will decrease the incidence of cervical cancer.

However, according to data presented recently at the annual meeting of the Society of Gynecologic Oncologists (SGO), there is already evidence that vaccination decreases the incidence of abnormal Pap smears and the number of procedures needed to evaluate these abnormal screening tests. This is tremendously important news. The cellular abnormalities detected by a Pap smear are clearly precursors of cervical cancer, so it is extremely likely that a decrease in abnormal Pap smears will directly lead to a decrease in cervical cancer.


This is what an abnormal Pap Smear looks like.
The red arrow points to a cancer cell.


But there are other important benefits from decreasing the frequency of abnormal Pap smears. In the words of Dr. Warner Huh, from the University of Alabama, Birmingham, “Very few of us can identify with cervical cancer, but almost every woman in the United States can identify with an abnormal Pap smear.” In fact, in the course of a lifetime, nearly 1 in 3 women will have an abnormal Pap smear and have to deal with both the procedures that are required to investigate the abnormality, and also with the anxiety of believing that she may have cancer. So, clearly, decreasing the rate of abnormal Pap smears would be a huge benefit to all women.

The benefits extend beyond avoiding anxiety and medical tests. There is a societal cost savings as well: According to the SGO, the combined costs of screening and treating cervical abnormalities in the US alone amounts to $4 billion per year. That’s quite an opportunity for cost reductions!

In related news, a report published this past week stated that as many as 1 in 4 teenaged girls in the US has a sexually transmitted infection. The medical blogosphere has been abuzz with this information and its implications.

At first blush, this is a horrifying statistic. After all, when most people think of sexually transmitted infections, they think of gonorrhea, Chlamydia, herpes or syphilis, and it would be awful to imagine that 25% of the teenaged girls in the US have one of these infections. However, HPV is included in the definition of sexually transmitted infections used by this report. As many as 80% of women in the US show evidence of having been infected with HPV at some point. Including HPV infections in the definition of sexually transmitted infections, then, will substantially distort the numbers. After all, by this definition, more than 80% of adult women in the US have an STI! Compared to that, 25% doesn’t seem as bad.

This number does, however, add to the importance of vaccinating girls against HPV. If girls are getting infected in their teenaged years, and if vaccination can prevent infection, abnormal Pap smears, future medical procedures, and hopefully the development of cancer, this suggests that vaccination should happen early (ages 8 or 9?), well before girls become sexually active, in order to maximize the benefits.

12 comments:

DermDoc said...

I thought there was data showing that it decreased the risk of cancer (not just HPV incidence).

Decreased risk of abnormal pap smears is yet another (did we need another?) reason to recommend this vaccine to all girls.

ArkieRN said...

Speaking as a cervical cancer survivor (who feels very lucky to still be here), please, please vacinate your children.

Jaime said...

Hey Doctor David ;)

Thanks for visiting my blog! I didn't comment and posted my own entry to refrain from hijacking your blog but I think this vaccine is wonderful and parents are foolish not to consider putting it to good use ;)

Anonymous said...

Isn't this a bit extreme? I myself am a cervical cancer survivor and I will NOT let my daughter have this. Cervical cancer kills only a very small portion of the population; the very old or already ill. It can be easily found with regular pap smears and easily treated. In 2000-2003 studies the ACS found that 70% of the cervical cancer patients were older than 40, which is outside Gardasil's protection range anyhow. Then there is also the fact that we are unaware of the long term affects this vaccine. A vaccine which only covers 4 of the 90 strains that can cause cervical cancer.

I wouldn't be so quick to call a mother, or any woman, irresponsible for not vaccinating her child with a medication for something that is easily treatable with proper education and that we are unaware of the long term effects are on our young girls. Perhaps if I saw more documentation and less rhetoric and hyperbole, I might change my mind. As it stands, I think I'm being extremely responsible by not removing the choice of what risks my child may want to take. In the meantime I'm being responsible and educating her. I'd definitely hesitate on using the word "foolish". I am at least trying to educate myself of all sides of this issue...I wasn't moved by some emotional appeal of my own history or some "One less" sound byte.

vehemently disagree said...

OK to the above commenter:

What happens if your child slips up? What happens if your child trusts her partner and her partner is unaware of their HPV status? What if, what if, what if. There are too many what ifs there that are worthy of avoiding a revolutionary vaccine that could prevent your child from debilitating chemotherapy or worse. Cervical cancer is frequently metastatic and aggressive, it is very difficult to treat.

The anti-vaccination movement, which is generally suspicious of the entire medical community, really needs to raise its blinders for the sake of their children's health education.

OK I see your 70% statistic from the ACS. OK, fine. What happens if your child is one of the 30% that develop cervical cancer way before they are geriatric? Again, cervical cancer is extremely difficult to treat, and there is an overwhelming amount of data that supports Gardasil's efficacy.

If your child develops cervical cancer at any point in their lives, why condemn them for their life choices? 1 out of 4 Teenage Girls is an EXTRAORDINARILY high statistic. It is not a statistic that is foreign from any of us, these are our daughters, our classmates, our nieces, our sisters, and strangers. Yes, it is foolish to just presume that we are separate from such an overwhelming statistic.

Your child can get the vaccine when she is an adult or when she has become sexually active. She can do both without your consent. So, don't tell her it is 'wrong' simply because it is a vaccine.

When I did a quick google scholar search for Gardasil, I found 1,420 scientific research studies. All such studies are rigorous, scientifically valid, replicable, reliable, and because of this, cannot just contain 'soundbytes' and rhetoric.

I strongly suggest you look beyond your cynicism and take a truly unbiased approach to researching the benefits of this vaccine.

This is nowhere near extreme. Most medical professionals, especially pediatricians, are talking about it amongst each other (so in scholarly settings) and also to their patients. For a pediatric oncologist to try and disseminate information that can potentially keep deadly cancer statistics down is far from extreme.

I don't want to inadvertently start a flamewar in this blog, but yes, intentionally not vaccinating your child because you don't want to and have not done the research is irresponsible and willful ignorance. To write the vaccine off entirely is irresponsible and foolish. To try and conduct serious research into why so many in the medical community support the Gardasil vaccine series + to talk to your doctors and THEN to form your own educated opinion about it (even if you still are not convinced) is responsible. I assume you have not done any of these things because you think being a proponent of Gardasil is extreme for a medical blogger to write.

Anonymous said...

Wow..assume wrong much?

The medical profession is not right simply because they are doctors. They have to rely on the voices of vested interests-pharma reps. Great, so the docs are talking about it. They don't know any more than the rest of us. They only know what Merck tells them, same as the rest of us. Again, no thorough documentation. I have done the research. I have found that the long term effects are completely unknown for any female. My child is not a guinea pig.

I have also found, through thorough research AND discussion with my doctor that my daughter being one of that 30% is only likely if she skips her regular exams (that you still have to undergo even with the shot) due to being poor, an immigrant, disabled, refugee, or completely irresponsible. Since we believe in education around my house irresponsibility is unlikely, as far as the rest, she's none of those.

I refuse to play "what if...?". It's a ridiculous question and we can throw them back and forth all day, neither of us will win.

I am not anti-vaccine. I believe in vaccines. My children are kept up to date because you can't be responsible and not get polio, nor is polio easily fixable. However, with an exam she has to get anyhow, HPV is easily found and can be taken care of. You are aware that all of us have had HPV at one time or another, right? Most women throw it off and have no idea they ever had it. When I say most, I 80%. We don't even notice it for the most part. Not every virus turns into cancer because either we throw it off naturally or it's caught at regular exams. 80% is a scary number unless you know the rest of the story. With regular exams, cervical cancer developing from HPV is rare.

Do you really think I should make my daughter a guinea pig over that? I'm sure you do, but I don't and won't. You see that as irresponsible, I see any parent going for this vaccine with the current information irresponsible. I think we'd have to agree to disagree there. I'm protecting my child BOTH ways, by eliminating the concern for future issues due to the vaccine and by teaching responsibility that will keep her from developing cervical cancer.

As far as your links of citations, I will hardly rely on google to tell me what's best for my child (especially since the majority of those are merely the same citation over and over).

Doctor David said...

Wow! How cool that my post generated such passionate reaction. I'm so glad that people come, read, think, and discuss. I just hope that the discussion can remain friendly... passionate, but polite.

Thanks!

Doctor David said...

I do have a few comments I would like to make in response to the preceding discussion:

1. It is important to keep in mind that the vaccine in question is meant to prevent infection with 4 strains of HPV. These strains were chosen because they are the most tightly associated with cervical cancer. It is not, however, a "cervical cancer vaccine."

2. The recommendation to give the vaccine is not being made by doctors who "only know what Merck tells them." It is being made by the ACIP, a group of vaccination experts who make recommendations based on a review of primary literature, not marketing materials.

3. As I mentioned here, HPV is becoming increasingly important as a cause of oral cancer. Unlike cervical cancer, there is no Pap smear equivalent for oral cancer, the treatment is not trivial, and the mortality is quite high.

4. The 4 strains of HPV included in the vaccine used in the US account for about 90% of the cases of genital warts.

5. The delay betwen acquisition of the virus (during teenaged years for many of the girls, apparently) and development of cancer speaks to the fact that more has to happen for a girl to get cervical cancer than just get the infection. However, the fact that the infection happens at a young age means that the fact that women develop cervical cancer in their 40's and older has no bearing on whether the vaccine is likely to prevent cancer or not.


According to the National Cancer Institute, 3,670 women will die of cervical cancer in 2007. I'm thrilled that cervical cancer rates are dropping and that early detection is making this far less deadly a disease in the US than it was in the past, but women still die of cervical cancer.

I do, however, take exception to referring to girls who get vaccinated after FDA approval of the vaccine as "guinea pigs." I'll address this topic more at a later date, but 1) because the vaccine has already undergone clinical trials, administration of the vaccine is not experimental, which is the implication of the phrase "guinea pig," and 2) patients who do enroll on clinical trials are research subjects, not guinea pigs, and in this country they or their parents have given informed consent to participate in these trials. Clinical trials are the reason cervical cancer is not the scourge (in this country) that it once was, and clinical trials are the reason childhood ALL which was once uniformly fatal is now curable 80% of the time. So please, please do NOT denigrate clinical trials by referring to participants as guinea pigs.

And my final thought... medical decisions are very individual. Some people will want to vaccinate their daughters (and maybe even sons) against HPV and others will not. I respect eveyone who makes an informed decision about this vaccine. It certainly sounds like my anonymous poster AND "vehemently disagree" are both informed. They reached different decisions. I think that's fine.

Jaime said...

To the Anon poster,

If your reference to the "foolish" statement came from my comment, I'd like to ask that you keep it in context.

As you said, you did you research, therefore you've "considered" whether or not to put it to good use.

Those who have not and only see the negative aspect of "my children are not sexually active and therefore do not need this vaccine" and don't look into the potential ramifications before making a decision are the ones I'd say are foolish for not considering putting this vaccine to good use.

Anonymous said...

Merck, The FDA and the CDC are only looking out for themselves. This is not an anti-cancer vaccine. Look at the Vaers data-base then decide if you want to be one less. One less living, One less healthy, One less productive, The Vaers back log is incredible. They are all funded by Merck, Have Merck interests and or royalties. I would not trust them. Well for all you gardasil lovers go vaccinate yourself, everyone you love and watch them die a slow painful death. If your promoting this lethal injection you should be tasting your own medicine. Go get the series of genetically altered DNA shots. Lets see if your immune system can handle it. I hope not.

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