Although most studies of the relationship between oral contraceptives (OCs) and breast cancer have focused on a possible causative role for OCs, new data suggest that breast cancer patients with a history of OC use may actually fare better than women who have never taken the pill.
The long-term survival advantage seen in OC users with breast cancer was independent of other, established prognostic factors, according to an analysis of 471 patients with breast cancer carried out at University Hospital Charlottenberg, Berlin, as part of the WHO Collaborative Study of Neoplasia and Steroid Contraceptives.
"I want to stress that we did not find any difference in the distribution of prognostic factors that could explain the difference in overall survival," Ines Schonborn, MD, said at the Eighth Annual European Cancer Conference (ECCO-8).
Although OC use correlated with increased histologic grade and younger age at the time of diagnosis, there were no links uncovered between OC use and tumor type, size, nodal status, or estrogen-receptor status.
Dr. Schonborn noted that the survival edge was particularly pronounced in women who had used OCs for more than 4 years, and most significant in patients who might have been expected to have a worse outcome, such as those with positive lymph nodes, large tumors, and hormone receptor-negative tumors.
"There may be a favorable effect of oral contraceptives on tumor biology or metastasis during the preclinical course of the disease," she proposed.