Strategies to lessen fetal risks during cancer Tx. (Excision, Nodal Sampling for Vulvar Ca).

BIG SKY, MONT. -- About 3% of breast and gynecologic cancers occur in conjunction with a pregnancy but many cancers can be adequately treated without jeopardizing the fetus, Dr. Lynn Montgomery said at an obstetrics meeting sponsored by Symposia Medicus.

Cervical cancers occur in about 1 in 770 pregnancies, and ovarian cancers occur in about 1 in 5,000-25,000 pregnancies. There have been only 24 cases of uterine cancer reported during pregnancy, said Dr. Montgomery director of obstetrics and maternal-fetal medicine at Rocky Mountain Perinatal Center in Missoula, Mont.

About 5% of patients undergoing a routine prenatal screen will have an abnormal Pap smear, which should be immediately followed by colposcopy. If colposcopy results suggest low-grade dysplasia, "many people, myself included, feel that biopsies are prudent at this point to ensure that the abnormal cytology is adequately identified," he said.

A directed biopsy is definitely indicated if the colposcopy suggests invasive or microinvasive disease, but endocervical sampling is contraindicated in pregnancy because it can rupture the membranes.

A cone biopsy can be done, using either a cold knife or the loop electrical excision procedure, if both biopsy and colposcopy have not adequately identified the cytology, but this carries a 5%-14% risk of hemorrhage and a 3%-6% risk of fetal loss or premature labor.

If the patient is diagnosed with either low-grade or high-grade dysplasia, it is safe to defer further intervention until the postpartum period. In this case, patients should be under colposcopic surveillance, and, if progression is noted, therapy should be considered.

Spontaneous regression is noted in up to 70% of cases, especially after a vaginal de livery. "I like to repeat both the Pap test and the colposcopy at 6 weeks post partum just to [get] extra confirmation," Dr. Montgomery said.