Vulvar Intraepithelial Neoplasia (VIN) and Cancer
Frederick R. Jelovsek MD
Vulvar disease and cancer is certainly not as frequent a problem as are abnormal Pap smears or abnormal uterine bleeding and the concern for endometrial cancer. And yet when the doctor says that a biopsy of the vulva is needed to make sure there is not a malignancy or changes that could become malignant, confusion and lack of knowledge are the rule. Vulvar cancer is only 1% of all female cancers and only represents 4% of all gynecologic cancers. Changes can take place in the vulvar skin just like the abnormal Pap smears and the dysplasia that occur on the cervix, albeit they are much more frequent in the cervix than on the vulva. Women are more aware of genital warts, condyloma accuminata, caused by the human papilloma virus (HPV) and the concern that they may be related to development of vulvar cancer in later life.
A recent review article, Chi DS:The diagnosis and management of vulvar cancer. Prim Care Update Ob/Gyns 1999; 6:24-32, has been quite helpful in answering some of the questions that come up when "vulvar biopsy" is mentioned.
What is vulvar intraepithelial neoplasia (VIN)?
Vulvar intraepithelial neoplasia is a preinvasive skin lesion of the vulva similar to cervical intraepithelial neoplasia (CIN) or dysplasia, that can occur in the cervix and result in abnormal Pap smears. It is diagnosed on biopsy the same way that CIN is diagnosed, i.e., how extensive the abnormal nuclear changes in the skin are. If only the bottom third of the epithelial (skin) lining has these changes, mild dysplasia or VIN I is diagnosed; if the full thickness of the epithelium has abnormal cells, VIN III, also called vulvar carcinoma in situ, is diagnosed. Just like in the cervix, if these vulvar changes are left untreated for many years, some of them turn into an invasive cancer in later years. Therefore doctors recommend excising that abnormal tissue so as to prevent any cancer from developing.
How can I tell if I have any vulvar dysplasia or vulvar cancer?
Chronic vulvar itching and burning or a slightly raised skin lesion are the most frequent findings of this problem. Usually the itching has persisted for years with perhaps multiple treatments with various skin creams. Lesions may be pink, red, white or gray in color. About 25% of lesions are hyperpigmented, appearing darkened like a mole or freckle. These more advanced, but noncancerous changes such as VIN III (carcinoma in situ) or actual cancer tend to occur at older ages. The average age of VIN III is 45-50 years of age while that of invasive vulvar cancer is about 65-70 years of age. As you can see, it takes, on the average, well over a decade for the severe preinvasive stage to go on to cancer if it is going to.
What causes vulvar dysplasia (VIN) and cancer -- is HPV involved?
More than one infectious agent has been suspected as the cause of vulvar dysplasia. Herpes simplex virus, granulomatous STD infections, and human papilloma virus have all been shown to be associated. In fact 80%-90% of all VIN has been shown to have HPV DNA present. Interestingly, only 30-50% of invasive vulvar cancers have been shown to have HPV DNA in them. Some experts have postulated that patients with squamous cancers of the vulva can be divided into two groups that may have different causes for their cancers. Younger women (35-55) tend to have cancers associated with HPV infection and VIN. The lesions are usually multifocal over various areas of the vulva. Older women (55-85) have more of a history of vulvar inflammation, itching and burning for many years and lichen sclerosis, a whitening skin change. Their cancers are usually unifocal and do not show evidence of HPV infection or vulvar intraepithelial neoplasia changes in the surrounding tissue.
How likely is it for vulvar intraepithelial neoplasia (VIN) to progress to cancer?
Overall, studies have shown that only 4% of women with VIN have gone on to have invasive cancer. You must remember though, that all of these women received treatment for the VIN. In one small study, 7 of 8 women who had VIN III and went untreated, went on to have invasive vulvar cancer. It would seem prudent to treat all VIN lesions but being careful not to mutilate the vulva in the process since VIN is quite curable.
How is vulvar dysplasia (VIN) treated?
The mainstay of treatment is to remove all affected tissue with a margin of at least 2-3 mm of normal tissue around the VIN. For multiple lesions (multifocal), laser ablation is the most common treatment because it can destroy the abnormal cells without going too deep into normal tissue. For fewer or unifocal lesions, surgical excision is often performed to get a little deeper into the tissue and make sure there is not an early invasive cancer.
Is vulvar cancer easily curable or is it a "bad actor"?
Like many cancers, curability depends upon how early a cancer is found and treated. If a vulvar lesion shows less than a millimeter of invasion it is completely, 100% curable. If it invades more than 5 mm (about 1/4 inch), lymph nodes will already have cancer in them 40% of the time. Vulvar cancer spreads to the inguinal (groin) lymph nodes and when it does, it really changes the survival. Over 90% of women with vulvar cancer who have no lymph node involvement will live over 5 years. Survival at 5 years decreases to 75%, 36%, 24% and 0% in women with 1 or 2, 3 or 4, 5 or 6, or 7 or more lymph nodes positive for cancer removed at surgery. This poor survival is why doctors recommend biopsy of any suspicious lesion on the vulva to pick up a cancer early.