For women survivors of breast cancer, subsequent pregnancy is not associated with worsened prognosis according to a study to be published in the journal Cancer.

The study, by Dr. L. Johnetta Blakely and colleagues from the University of Texas M. D. Anderson Cancer Center in Houston, found pregnancy did not increase the risk of recurrence or mortality, providing significant evidence to allay women's fears about having children after treatment for breast cancer.

One quarter of the more than 211,000 new cases of breast cancer expected in 2003 will be diagnosed in women of childbearing age. About half those treated with chemotherapy will experience amenorrhea (loss of menses) and ovarian dysfunction, making future pregnancy impossible. The rest, more than 25,000 women a year, will still be able to have children, but may be uncertain about pregnancy's effect on their own health.

Because pregnancy raises the level of hormones that often mediate breast cancer, and because breast cancer survivors face a higher risk of recurrence, especially in the first five or ten years after diagnosis, physicians have traditionally recommended that survivors not get pregnant. Small, retrospective studies, which are notoriously difficult to interpret, have suggested pregnancy does not increase the risk of recurrence or mortality after treatment for breast cancer. But as more women wait longer to start families and as breast cancer survival improves for pre-menopausal women, a more conclusive answer is needed. Blakely et al. investigated a large patient population over 22 years to assess the effects of pregnancy on subsequent cancer risk for women under 35 years old who had previously been treated for breast cancer.

The study found patients who were treated for breast cancer and had a subsequent pregnancy did not have an increased risk of death or recurrence. The risk of recurrence in survivors who subsequently had a pregnancy was 23 percent compared to 54 percent for survivors who did not. The low overall risk associated with pregnancy is most likely strongly influenced by selection, i.e. survivors with the best prognosis may be more likely to consider pursuing pregnancy. Those women who did have a pregnancy and subsequent recurrence tended to have earlier stage disease and fewer positive lymph nodes, and more often had estrogen receptor negative breast cancer.

The authors conclude, "These data suggest that subsequent pregnancy after adequate therapy for breast cancer is not associated with an increased risk of death or recurrence."

SOURCE:
Cancer, February 1, 2004