Oral contraceptives and breast cancer. Progress report of an epidemiological study.

322 women aged 16-45 years undergoing treatment for newly diagnosed breast cancer, together with 502 matched control patients, have been interviewed at six hospitals. The data suggest that the use of oral contraceptives is unrelated to the risk of breast cancer. While this result is reassuring, it is important to remember that it mst be many years yet before the question of the possible relation between oral contraceptives and breast cancer is finally settled.