Sex of first child as a prognostic factor for breast cancer in young women.

In a study in upstate New York, incidence and survival rates of 317 young women (less than 45 years), diagnosed with breast cancer, were examined in relation to the sex of each woman's first offspring. While incidence of breast cancer was not found to be affected by the sex of the first child, prognosis was poorer when the first child was made (p less than 0.05). The authors examined the effect of stage at diagnosis, interval between first pregnancy and diagnosis and concurrent pregnancy at the time of diagnosis as factors other than sex of first offspring that might have an additional influence on survival. Among these, only interval had an effect, and it was of weak statistical significance (0.05 less than p less than 0.1). These findings regarding survival in relation to the sex of the offspring are opposite to those reported recently in France by Juret et al. (Lancet 1:415-416, 1978). Possible differences between the two studies which may account for the opposite findings are discussed.