EFFECT OF PREGNANCY ON PROGNOSIS FOR YOUNG-WOMEN WITH BREAST-CANCER

Breast cancer in women under 30 years old carries a poor prognosis, fo r reasons that have not been identified. This study aimed to identify prognostic factors in this age group. Special attention was paid to th e history of pregnancy. The clinical presentation and course of breast cancer was documented for 407 women, aged 20-29 years, who registered between 1978 and 1988 at one of nine cancer centres. Eligible patient s had histologically confirmed local or regional invasive breast carci noma, and received part or all of their initial therapy at the partici pating hospital. For patients whose breast cancers were diagnosed duri ng pregnancy, the risk of dying from breast cancer was significantly g reater than that of women who had never been pregnant (relative risk 3 .26 [95% Cl 1.81-5.87], p = 0.0004). Adjustment for number of axillary nodes affected and tumour diameter reduced the relative risk only sli ghtly (2.83 [1.24-6.45], p = 0.023). For each 1-year increment in the time between the latest previous pregnancy and breast cancer diagnosis , the risk of dying decreased by 15% (relative risk 0.85, p = 0.011). Thus concurrent or recent previous pregnancy adversely affects surviva l of breast cancer in young women. The size of the effect is such that it probably contributes substantially to the poor prognosis of breast cancer in this age group as a whole.