A 15-year study published in the June 1, 1999, issue of Cancer offers further hope to premenopausal breast cancer patients who might want to bear children. According to the study of 520 women £ 40 years old, pregnancy after breast cancer diagnosis and successful treatment does not increase a patients risk for recurrence or death from the disease. This is particularly true for women with local disease at diagnosis.
Of the 53 study women who became pregnant after being diagnosed with breast cancer, 68% delivered one or more live-born infants. The miscarriage rate (24%) among these women was 70% higher than expected, however. Chemotherapy or the radiation used to treat breast cancer may be associated with the increased miscarriage rate. Of the 36 women who gave birth to a live infant, 5 died of their breast cancer. There was a 0.8 chance of death associated with any subsequent pregnancy in this population.
The results of our study support the growing consensus that subsequent pregnancy does not have an adverse effect on survival after breast carcinoma, particularly among women with local disease, said study coauthor Priscilla Velentgas, PhD, Department of Biostatistics, University of Washington, Seattle.
Study Protocol and Limitations
Researchers reviewed completed questionnaire, interview, and cancer registry information from 520 western Washington women diagnosed with stage I or II breast cancer between 1983 and 1992. The women had been followed for breast cancer deaths through April 1998. All of the women were 40 years of age or less, premenopausal, had not undergone surgical removal of their reproductive organs, and were not pregnant at the time of their initial breast cancer diagnosis.
In the June 1 issue of Cancer, an editorial commends the current study but also notes its limitations. [This study] comes at a time when American women are opting for later childbirth and the incidence of breast carcinoma continues to rise in all age groups, said editorial coauthor Hervy B. Averette, MD, Division of Gynecological Oncology, University of Miami School of Medicine, Florida. Dr. Averette added, Approximately 25% of women will develop a breast cancer in their premenopausal years and still may wish to bear children. However, a major 1994 study suggested that hormones involved in pregnancy might promote hidden cancer development. That studys researchers noted that patient survival was better proportionately with up to a 4-year interval between breast cancer diagnosis and subsequent pregnancy. Yet to our knowledge, there are seven published reports implying that subsequent pregnancy after breast carcinoma is safe when corrected for stage of the tumor.
The editorial also points out the current studys limitations, such as its retrospective data that are based on memory of the treating physician, review of hospital records, and/or interview with family members. Furthermore, the potential for selection bias in these retrospective studies is enormous.