Vulvar Cancer and Human Papilloma Virus (HPV)
By Frederick R. Jelovsek, M.D.
As with other genital cancers, vulvar cancer has a preinvasive phase in which changes can be detected in the skin of the vulva that precede an invasive malignancy. This preinvasive phase is called vulvar intraepithelial neoplasia (VIN). Human papilloma virus (HPV) has been suspected in playing a role in causing this rare cancer and some studies show that the DNA of a specific subtype of the virus (HPV-16) can be recovered in up to 80% of vulvar cancers. In one study by A. Hildesheim and others, Human Papillomavirus Type 16 and Risk of Preinvasive and Invasive Vulvar Cancer: Results From a Seroepidemiological Case- Control Study. Obstet Gynecol 1997; 90:748-54, the presence of blood HPV-16 antibodies were measured in patients who had recently diagnosed severe preinvasive vulvar dysplasia (VIN-3) and invasive cancer. They were compared to other paitents from the same geographical area that didn't have vulvar disease.
The authors found that more patients with vulvar disease had antibodies to HPV-16, i,e, they had been exposed to the virus at some time in the past. The risk ratio for preinvasive vulvar disease was over 20 times if a woman had HPV-16 antibodies. This was higher than even the risk for invasive cancer. Smoking and another virus antibody, herpes simplex virus type 2, were also independent risk factors. While the study didn't find as high a risk ratio for invasive vulvar cancer in general, it did find a higher risk for a type of vulvar cancer, a squamous carcinoma of a basaloid or warty type, more so than for a type called keratinizing squamous cell carcinoma.
What do these findings mean? They don't necessarily mean that HPV-16, HSV-type 2 and smoking cause vulvar cancer. They are somehow associated at with preinvasive vulvar cancer and possibly with one subtype of vulvar cancer. Smoking may suppress the local immune system and permit these viruses to induce skin cellular changes that can go on to cancer after many years. No one is absolutely sure. It does make another case against smoking, however. Also, venereal warts - condyloma accuminata - are thought to be caused by HPV virus and a woman that has a history of those warts should probably consider herself at higher risk for vulvar cancer as should a woman who has had a history of vulvar herpes lesions. A woman with a history of these problems doesn't need to panic, however, because these are still quite rare lesions that occur in the age decade of the 70's. Many more woman have these infections when younger and only a very small number ever develop a cancer.
If a woman has a history of such infections and especially if there is a recent smoking history, it would be wise to do regular self-exams of the vulva and to continue an annual physician visit after the age of 60 which includes the vulvar exam. Most vulvar cancers that physicians newly diagnose are women in their 70's and 80's who had quit going to their doctor for regular pelvic exams for many years.
See also Risk for vulvar cancer.
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