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May 15, 2007
the FUTURE of HPV
Wow. Speaking of great study names, the NEJM published reports on two large ongoing trials on the HPV vaccine. Females United to Unilaterally Reduce Endo/Ectocervical Disease I and II (which they call FUTURE I and II). They are looking at meaningless histological endpoints again, but include adenocarcinoma in situ. Looking at the higher grades there is no benefit so far to the vaccine (which is not their conclusion). To what I wrote earlier, I will add this.
The findings of the FUTURE, even interpreted in the most favorable light, pale when set against the risks and harms. It is projected that about 11,000 US women will be diagnosed with invasive cervical cancer this year. Of these about a third will die.
So to find the 1/10,000, it is urged that every woman receive an annual Pap smear. This obviously ignores that only women with high-risk HPV types are even at risk. It also ignores that it takes ten to twenty years for the cancer to develop. Even worse, it ignores the number of false positives that are found and must have follow-up testing, at a huge psychological cost (of thinking she is dying of cancer for the weeks or months the follow-up takes) and financial and physical and social costs. And what of the harm of the LEEP or cryo or other modality? These obscure further testing, and create harm of their own.
"Annually in the US, about 50 million women undergo screening; about 3.5 m (7%) will be referred for further evaluation. Of these, more than 2 million will be referred for further evaluation of ASCUS.� 2 million unnecessary colposcopies? Or cryotherapy, which is associated with PID & cervical stenosis, and which makes subsequent colposcopy inadequate. A complication rate of 5-20% means 25-100,000 unnecessary complications to prevent a few deaths. Or even up to 11,000.
Then there is the accuracy issue. Estimates vary, but using higher grade lesions PAP has a sensitivity of 70-80% and specificity of 95%. (68 and 75 more realistically). With a prevalence of 6/10000 CIN3, the Positive predictive value of the PAP is 1%.
So we scare everyone into getting a test that is only right 1/100 times when it's positive, to send 2 million women for further testing, which harms 200,000 of them, to prevent potential cancer two decades later in maybe 11,000 (though the nonvaccine oncogenic types will undoubtedly increase in significance). Have we gone mad?
| By Robert Maddox | 05:24 PM
Comments
Posted by: Emeth Hesed at June 14, 2007 03:14 AM