Pregancy after breast cancer diagnosis and successful treatment, particularly when the cancer is confined to the breast, does not increase a woman's chance of recurrence or death from the disease, according to researchers at the Fred Hutchinson Cancer Research Center and the University of Washington.
The results of this 15-year collaborative study appear in today's issue of CANCER.
The study was co-authored by Drs. Janet Daling, an epidemiologist at the Hutchinson Center and UW, and Priscilla Velentgas, a UW biostatistician, among others.
While the study offers further hope to premenopausal breast-cancer patients who might want to bear children, it indicates the miscarriage rate is higher than expected among women who conceive after undergoing successful treatment for breast cancer.
The study involved more than 500 women age 40 or younger treated for early stage breast cancer. Sixty-eight percent of the 53 women who became pregnant after breast-cancer diagnosis delivered one or more live-born infants. But among these women, the miscarriage rate (24 percent) was 70 percent higher than expected. Chemotherapy or radiation used to treat breast cancer may be associated with an increase in the miscarriage rate, according to the study.
Five of the 36 women who had given birth to a live infant died of their breast cancer. There was a 0.8 percent chance of death associated with any subsequent pregnancy in this population.
Researchers reviewed completed questionnaire, interview and cancer-registry information regarding 520 women in western Washington, all of whom were diagnosed with breast cancer between 1983 and 1992. These women were diagnosed at Stage I (when the tumor is about an inch in diameter has not spread outside of the breast) or Stage II (when the cancer is between 1 and 2 inches in diameter and may have spread to an underarm lymph node). The women were followed for breast cancer-related deaths through April 1998. The women were age 40 or younger, pre-menopausal, had not undergone surgical removal of their reproductive organs and were not pregnant at the time of their initial breast-cancer diagnosis.
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