GENDER OF THE FIRST OFFSPRING, AGE AT DIAGNOSIS, AND SURVIVAL WITH BREAST-CANCER (UTAH, UNITED-STATES)

We examined the relationship between the survival of women with breast cancer and the gender of their first children using a genealogy-based survival analysis. The study group consisted of 2,155 parous women di agnosed in Utah (United States) with first primary breast cancers (exc luding in situ tumors). We calculated hazard rate ratios (HRR) which w ere adjusted for stage, median survival times, and proportions survivi ng for three-, five-, and 10-year intervals stratified by age at diagn osis. Median survival among women diagnosed under the age of 45 was 17 1 months if the first child was female, but only 66 months if the firs t child was male (HRR = 1.66, 95 percent confidence interval = 1.07-2. 57, for male children). For women diagnosed at age 45 or older, all su rvival times were similar, although women whose first child was male h ad slightly longer median survival time. These findings suggest that t he gender of the first child has a strong influence on survival among women diagnosed under 45 years of age, but not among those diagnosed l ater in life. Gender of the first offspring may be a useful clinical i ndicator of prognosis and survival and may provide insights into etioI ogic and promotional factors for breast cancer.