Since virtually all cervical cancers are caused by human papilloma virus, why don't doctors just test for HPV instead of doing Pap smears? Since most women aren't infected, wouldn't it make more sense to screen for HPV, then do a Pap smear only if the HPV test was positive? Also, since cervical cancer is a sexually transmitted disease, what is the point of doing Pap smears on virgins? And why should they be done on women who have been in a totally monogamous relationship and have had previous normal smears?

-- Amanda

While it is true that HPV (human papilloma virus, the virus that also causes genital warts) is implicated in many cases of abnormal Paps, it is not correct to say that virtually all cervical cancer is caused by HPV. Many women with abnormal Pap smears will have no evidence of the HPV virus.

Meanwhile, testing for HPV does not necessarily provide a great deal of information as a screening tool; HPV is extremely common in today's population, but not all women with HPV will ever have an abnormal Pap, much less go on to develop cervical cancer. There are many, many subtypes of the HPV virus, and of those, three to seven are considered aggressive or high-risk subtypes, more likely to produce severe dysplasia (abnormal cells) on a Pap or even cervical cancer.

Moreover, testing for HPV is more expensive than doing a Pap smear. In my area, a Pap smear costs the patient about $25, while the charge for HPV testing can be $400! All things considered, using the Pap smear for mass screening is much more economically sensible. It reveals specific dangerous changes, and it detects abnormalities in women both with and without evidence of HPV.

In a woman who has an abnormal Pap and has evidence of HPV, either by past history or by the way the Pap looks, additional testing for HPV subtype can be very useful. Women who have one of the low-risk HPV subtypes may choose to have no immediate treatment and just close followup, while women with a high-risk subtype may be better off having aggressive treatment.

A visit to the gynecologist before becoming sexually active is a good idea, as contraceptive options and safer sex can be discussed, but a Pap smear in and of itself may be deferred until after sexual activity begins. However, you'd be surprised how many "virgins" come in who really aren't virgins! Some women believe that if a man penetrates but does not ejaculate that she is still a virgin and is also safe from sexually transmitted diseases (STDs) -- not so! Also, "close to sex," as I like to call intense foreplay without actual vaginal penetration, can lead to infection with STDs, including genital warts (caused by HPV).

A woman who is in a current mutually monogamous relationship also is not free from risk of HPV or abnormal Paps. It may take years for an abnormality to show up on a Pap smear; thus, being exposed to HPV at age 19 may not lead to an abnormal Pap until age 30. Even if the woman was a virgin and this is her first relationship, she is at risk for contracting HPV or another STD from her partner if he had other partners -- even one -- before her. Of course, if both partners were really virgins and had not had even "close to sex" with anyone else before, then risks are low.

The bottom line is that a Pap smear is a worthwhile screening test for all women who are now or who have ever been sexually active. "Sexually active", by the way, does not mean "promiscuous"; sexually active means having had sex, even just one time or only with one partner.