Pregnancy and Cancer Treatment Often Are Not Mutually Exclusive

by David Galloway

Pregnancy, with its combination of physical and hormonal changes, is hard enough on a woman’s body. The last thing a mother-to-be needs is the added complication of cancer. Unfortunately, about one in every 1,000 pregnancies does coincide with cancer. Often, these women are advised to terminate their pregnancies, but many women are able to undergo effective treatment for their cancer and deliver a healthy baby.

“We continue to see patients, and the first thing that has been recommended to them is that they terminate the pregnancy. And for some people, that may be their choice, and that may be what they want to do,” said Richard L. Theriault, D.O., a professor in the Department of Breast Medical Oncology at The University of Texas M. D. Anderson Cancer Center.

“Depending on the stage of their cancer and their medical health, ending the pregnancy may be appropriate,” added Karin M.E.H. Gwyn, M.D., an assistant professor in the Department of Breast Medical Oncology and the Department of Epidemiology, “but it is not always necessary.” Pregnant women can undergo biopsies and even be treated for cancer with chemotherapy.

The cancer most commonly diagnosed during pregnancy is breast cancer, followed by cervical cancer, then lymphoma and thyroid cancer. Less common are leukemia and melanoma. With the exception of most cases of cervical cancer, pregnancy and cancer treatment are not mutually exclusive.

“In cervical cancer, the standard treatment is surgery [radical hysterectomy] and radiation,” Dr. Theriault said. “The issue is that the fetus is going to die from the treatment, except in unusual circumstances where the cancer is diagnosed early through a Pap smear and you are able to remove all the cancerous tissue with a cervical core biopsy and maintain the pregnancy and delivery.”

The outlook is much better for patients with breast cancer. Drs. Theriault and Gwyn work with women who have been diagnosed with breast cancer during pregnancy. Since 1989, their group has treated more than 50 such women. Most of the cancers they see are already at an advanced stage at the time of diagnosis, in part because both patients and physicians tend to dismiss breast lumps during pregnancy as changes related to the pregnancy. “They put it down to mastitis, blocked milk duct, some other reason,” Dr. Theriault said. He also cites a common fallacy that even if there is an anomaly in the breast, nothing can be done about it while the woman is pregnant. Some physicians will not even do a biopsy until after delivery, Dr. Gwyn said, further delaying diagnosis and treatment. Both recommend that all pregnant women be given a thorough clinical breast examination on their first visit to the obstetrician, when the women are still early in their pregnancies and the breasts have not yet become engorged.

The incidence of breast cancer concurrent with pregnancy is expected to increase as more women delay childbearing and as mammographic screening increases. The National Cancer Institute’s Surveillance, Epidemiology, and End Results Program’s Cancer Statistics Review found that women who have their first full-term pregnancy after age 30 have a two to three times higher risk of breast cancer than women who have their first pregnancy before age 20. Among the women in the M. D. Anderson cohort, the median age is 33, and the oldest woman among the patients is 42. As a result, Dr. Theriault urges increased suspicion of any changes in the breasts of pregnant women in their 30s or 40s.

When an anomaly is found, Dr. Gwyn recommends that obstetricians seek the help of cancer specialists rather than keep the burden of diagnosis on themselves. Accurately reading a mammogram or an ultrasound of a pregnant woman’s breast is difficult and requires experience, as does interpreting the results of a biopsy from a lactating breast.

If a pregnant woman is found to have breast cancer, chances are it will be an aggressive cancer. That unfortunate fact is not related directly to the pregnancy but rather to the age of the patients. “The tumors occurring in pregnant women are no different than the tumors occurring in other young women,” said Lavinia P. Middleton, M.D., an assistant professor in the Department of Pathology, “but breast cancer in young women is a histologically aggressive disease, so it’s more the age of the patient than her pregnancy status that affects the tumor’s growth and prognostic markers.”

If the tumor is found early, though, that histological aggressiveness can be to the patient’s advantage. “Tumors that have aggressive histological features, it sounds like they are bad tumors, something that you don’t want to have,” Dr. Middleton said. “But actually they may respond better to chemotherapy because of the rapid turnover of the tumor cells.”

The preferred treatment for a woman diagnosed with locally advanced or node-positive breast cancer during pregnancy is chemotherapy after the first trimester, followed by surgery, usually after childbirth. Radiation therapy is typically not used until after delivery in pregnant patients. The chemotherapy administered is a standard breast cancer treatment combination of 5-fluorouracil, doxorubicin (Adriamycin), and cyclophosphamide (FAC). “We give it the way that we would give it to a nonpregnant woman, and we use the same dosages that we would use for a nonpregnant woman,” Dr. Gwyn said. Taxanes are not approved for use in pregnant women, so patients with node-positive disease are given FAC during pregnancy and a taxane after delivery.

The fear that chemotherapy will have adverse effects on the unborn child has been somewhat relieved by a follow-up survey among the patients in the M. D. Anderson cohort. Of the 27 children included in a survey of their parents or guardians, all but three were reported healthy and developing normally. The only exceptions were one child with Down’s syndrome, which Dr. Gwyn said has nothing to do with chemotherapy, and two children with attention deficit disorder, which is not uncommon. One question that remains unanswered is whether the fertility of these children will be affected, because the oldest child from this study is only 13 years old. However, the researchers are encouraged by the results of a study of pregnant patients with lymphoma who were treated with chemotherapy. Their children have been monitored for more than 18 years, and some of them have already demonstrated fertility.

With the proper attention and a high index of suspicion, more of these aggressive breast tumors can be caught early. “Even with those negative prognostic attributes and characteristics, these tumors still can be treated successfully,” Dr. Middleton said. “And the patients can go on to lead productive lives.”

For more information on this topic or for questions about M. D. Anderson’s treatments, programs, or services, call askMDAnderson at (877) MDA-6789.

Other articles in OncoLog, January 2004 issue:

• Studies of the Viral Origins of Some Cancers Lead to New Prevention, Treatment Stategies
• House Call: Cancer and Your Weight
• DiaLog: Treating Breast Cancer during Pregnancy

ARRIBA

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