Serum testosterone levels and breast cancer recurrence.

Prospective studies show that high serum levels of androgens and estrogens are associated with increased incidence of postmenopausal breast cancer. The aim of the present analysis was to study the prognostic value of serum testosterone, estradiol and related factors in postmenopausal breast cancer patients. One hundred and ten patients without clinical recurrence were included in the study. After 5.5 years of follow-up, 31 patients developed distant metastasis (16), local relapse (4), or contralateral breast cancer (11). The risk of adverse events in relation to hormone level was examined by Cox' proportional hazard modeling, adjusting for hormone receptor status and stage at diagnosis. Body mass index and serum levels of testosterone, estradiol and glucose were significantly higher in patients who recurred than those who did not. The hazard ratios were 1.8 (95% CI = 0.5-6.3) for the middle and 7.2 (95% CI = 2.4-21.4) for the upper tertiles of baseline testosterone distribution. Other hormones had only minor influence on prognosis. High testosterone predicts breast cancer recurrence. Further studies are required to determine whether dietary or other medical intervention to reduce testosterone can reduce the recurrence of breast cancer.