Relationship between oral contraceptive therapy and estrogen receptor status in patients with breast cancer.

BACKGROUND: Breast cancer (BC) is the most common cancer in women, and the hormone receptor status is one of the most important prognostic factors in patients with BC. The aim of this study was to establish whether a relationship exists between the hormone receptor rate and the main classic risk factors in patients with BC. PATIENTS AND METHODS: The data regarding a series of 351 consecutive women (median age 57 years, range 26-85 years) who had undergone curative surgery for primary BC was retrospectively reviewed. Eighty-seven (24.8%) patients used oral contraceptives. According to the duration of OC therapy, the patients were dichotomized into two Groups. Group A: less than 22 months (47 patients, 54%) and Group B: 22 months or more (40 patients, 46%). RESULTS: Final pathology showed 15 (4.3%) pT1a, 62 (17.7%) pT1b, 133 (37.9%) pT1c, 125 (35.6%) pT2, and 16 (4.5%) pT3 BC. There were 286 (81.5%) infiltrating ductal, and 24 (6.8%) infiltrating lobular breast carcinomas. The average estrogen receptor (ER) and progesterone receptor (PgR) rate was 59.7 +/- 32.8 and 54.2 +/- 33.9, respectively. There was no relationship (p = NS) between either ER or PgR and the age of the patients, age at menarche and menopause, number of pregnancies, age at first pregnancy, number of spontaneous abortions, months of breastfeeding and the use of estrogen replacement therapy. As expected, ER and PgR rates correlated significantly (R = 0.78, p < 0.01). The ER rates of groups A and B were 51.7 +/- 35.6% and 68.2 +/- 23.6%, respectively (p = 0.014). No other differences (p = NS) between the groups were found. CONCLUSION: The prolonged use of oral contraceptives may increase the ER rate within the tumor tissue, and thus such therapy should be considered an indirect positive prognostic factor in patients with BC.