Reproductive history and stage of breast cancer

A woman's reproductive history influences her risk of breast cancer, The au thors hypothesized that reproductive history also influences stage of disea se at the time of diagnosis. The authors analyzed a population-based cohort of 1.5 million Danish women born between 1935 and 1978 for whom individual information on births was available. Between 1978 and 1994, 10,790 inciden t cases of breast cancer in women under 60 years of age were identified. Nu lliparous women compared with parous women and women with a late age at fir st birth compared with an early age were at significantly increased risk of being diagnosed with a large tumor and with cancer that had spread to regi onal lymph nodes, However, such an association was not seen for women diagn osed with a small tumor and women with cancer that had not spread to region al lymph nodes. Reproductive history did not appear to influence the time i nterval from first symptoms to first physician visit ("patient delay") or t he time interval from first physician visit to surgery ("doctor delay"). Th e authors conclude that reproductive history is associated both with incide nce of breast cancer and with stage of the disease at diagnosis, indicating possible influences on-tumor progression and growth rate. Intensified awar eness is warranted to achieve earlier diagnosis among nulliparous women and women with a late age at first childbirth, with the hope of improving thei r prognosis.