Q. I'm a 51-year-old woman who had a hysterectomy several years ago for fibroid tumors. Since then, my gynecologist continues to recommend that I have check-ups twice a year, including a Pap smear, even though I no longer have any risk of cervical cancer. He says he is checking for vaginal cancer. Could you please publish the medically recommended guidelines for how often gynecologic checkups of healthy women of various ages need to be done. Specifically, how often should Pap smears be done for a woman in my situation? How common is vaginal cancer?

A. Your question touches on several issues related to Pap smears and routine health checks for women. But unless you have some unusual risk factor for vaginal cancer, a Pap smear every six months seems excessive. No official organization calls for them so often in otherwise healthy women, even in those with a cervix, as long as previous Pap smears have been normal.

Several national organizations have agreed on how often Pap smears should be done. The organizations include the American Academy of Family Physicians, the American Cancer Society, the American College of Obstetricians and Gynecologists, the American Medical Association, the American Medical Women's Association, the American Nurses Association and the National Cancer Institute. These groups advise all women to start having Pap smears once they have intercourse or reach age 18. At first, women should have a Pap smear once a year for three years in a row. If these smears are normal, they may be done less often, as recommended by their physician.

The most recent official guidelines are from the U.S. Preventive Services Task Force, an expert panel endorsed by the Department of Health and Human Services. This group studied the scientific evidence for more than 100 preventive procedures. They recommend Pap smears every one to three years, based on a woman's risk factors and the advice of her physician. Risk factors for cervical cancer include having multiple sexual partners, beginning intercourse at an early age and having a cervix infected by the papilloma virus, which is thought to trigger cancerous growth.

So far, I've only talked about Pap smears, which screen for cancer of the cervix. General health checks for women are a slightly different story. The task force recommends focused health checks every one to three years for women age 19 to 39. Included in these checks are breast exams for women with a family history of breast cancer and Pap smears as outlined above. Between 40 and 65, the task force suggests annual breast exams for all women and Pap smears every one to three years. Mammograms are recommended every one to two years beginning at age 50.

Some medical organizations believe these guidelines may be too conservative and recommend more frequent visits. For example, the American Cancer Society recommends a first mammogram between ages 35 and 40, a mammogram every one to two years from 40 to 49, then yearly thereafter. The ACS recommends breast exams in all women every three years between ages 20 and 40 and annually thereafter.

Because you no longer have a cervix, the need for further Pap smears is debatable at best. Many doctors would say the need for a Pap smear no longer exists after a hysterectomy for a noncancerous condition. Many would continue doing pelvic exams without a Pap smear. Some, however, would still want a Pap smear to look for cancer of the vagina.

But no group endorses the use of Pap smears to screen for vaginal cancer, which is rare. It accounts for about 7 percent of female genital cancers and less than half a percent of all cancer deaths in women. When it occurs, the disease is usually visible to the naked eye. In other words, Pap smears aren't generally useful in detecting cancer of the vagina that's not otherwise apparent. Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center and Providence Hospital in Northeast Washington.

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