Woman's WorldWoman's WorldBy Jean Talbert, M.D.
The Human Papilloma Virus (HPV) is one of the most common sexually transmitted infections in the United States. Over 30 types of HPV can infect the genital area and these can be divided into two groups: low and high risk.
Low-risk types cause benign genital warts (condyloma) and/or microscopic changes on the cervix known as mild dysplasia. Infection with high-risk virus can lead to moderate or severe dysplasia, and ultimately cervical cancer. About 60 percent of men and women infected with HPV are completely asymptomatic.
HPV infection is most commonly acquired by young adults who are sexually active. The virus is transmitted by direct skin-to-skin contact, commonly from an asymptomatic carrier. Non-genital HPV, such as common warts on the hands, usually cannot be transmitted to the genitals. Genital HPV infection has been found to be present in approximately 40 percent of women between the ages of 18 and 40. Risk factors for infection include multiple (more than three) sexual partners, a partner who has had multiple sexual partners, and immunocompromise, such as HIV infection. Condoms, although protective for a number of sexually transmitted diseases (STDs) do not completely protect against HPV transmission. Although tobacco use does not cause HPV infection, it may contribute to progression of disease.
Fortunately, 70-90 percent of HPV infections in adolescents are asymptomatic and transient. Most will clear spontaneously within 12- 24 months. Women over age 21 with HPV infection are more likely to have persistent disease and are at a greater risk of progression.
When symptomatic, low-risk HPV infections manifest as genital warts. These condyloma may appear weeks to years after initial contact with an infected partner. Treatment options include observation (many condyloma will regress spontaneously), topical treatments or surgery. Topical treatments can be divided into home therapy or office-based therapy. Two home therapies are available – podofilox (a medication that blocks cell division) or imiquimod (an immune system stimulator). Both are applied directly to the lesion by the patient. The main side effect is local irritation. These treatments are effective in 60-80 percent of patients within four months, but there is a recurrence rate of 25 percent. Home therapy, of course, has the advantage of privacy.
Office-based treatments include freezing and topical application of caustic acid or chemotherapy agents. These methods often achieve a more rapid response, but are not practical for extensive disease. Surgical treatments such as excision and laser vaporization are reserved for extensive disease or patients who cannot tolerate other therapies.
High-risk infection is a major factor in the development of cervical cancer.
Some studies also suggest an association with anal, vulvar, vaginal, penile and some throat cancers. Fortunately, most of these cancers are very slow to develop and can be detected in the precancerous dysplasia stage.
Cervical dysplasia is typically detected by a Pap smear. Treatment involves microscopic evaluation called colposcopy. Biopsies then are taken to confirm the diagnosis. Mild dysplasias are caused by either high or low-risk virus. Mild dysplasia is typically followed with serial Paps and colposcopies as 50-60 percent will regress spontaneously. Moderate or severe dysplasias are treated with freezing, laser or local excision (LEEP procedure or cone biopsy) to prevent the risk of progression to cancer.
Recommendations for cervical cancer screening have changed over the past few years as we’ve developed new testing methods and learned more about the natural history of HPV infection. HPV DNA probes now can detect the presence of HPV even when there are no cervical changes. As transient HPV infection is so common in young sexually active women and cervical cancer in this age group is rare (less than 1.7 cases cases/100,000 women under age 24) the American Cancer Society recommends beginning Pap smear screening three years after the onset of sexual activity or by age 21. This will eliminate the need to do colposcopy and biopsies on many young women with transient infection. Screening for other STDs and contraceptive counseling should still be offered at least annually to sexually active teenagers.
All women between 21 and 30 should have annual Paps. Paps that show mild abnormalities should have a reflex test for HPV virus to determine if that is the cause. Abnormal Paps with a positive test for high-risk HPV or Paps showing dysplasia should be referred for colposcopy. Women over age 30 may be screened with either annual Paps or a combination of Pap and HPV tests. If both are negative, rescreening is not necessary for three years. Although the Pap may not need to be performed annually, a pelvic exam and breast exam are still recommended each year.
Pap and HPV screening programs have been very successful in decreasing the rates of cervical cancer in the United States. Unfortunately, cervical cancer is still a major cause of death of women in the developing world. The development of an HPV vaccine is under active investigation and researchers report very promising preliminary results. The goal will be to vaccinate young girls before they are sexually active and therefore, at risk of sexual transmission of HPV. Hopefully, vaccination against this disease will become a reality in five to 10 years.
(Dr. Talbert is a board certified OB/GYN specialist practicing with Cape Obstetrics, Midwifery & Gynecology in Falmouth and Sandwich, 508-457-0088.)