Long-term relapses in breast cancer patients (estrogen receptor status)

To investigate the relation between estrogen receptor (ER) status and timing of relapse, we retrospectively studied two groups of patients (200 cases in each group) who underwent radical mastectomy and developed an early relapse (within 3 years of the surgery) or a long-term relapse (more than 8 years after surgery). One-hundred and eighty-two (91%) patients who developed a long-term relapse were ER-positive (ER+), whereas only 64% of patients who developed an early relapse were ER+ (P < 0.001), supporting the hypothesis that a long-term relapse is more frequently associated with an ER+ tumor. A review of the literature, which indicated that a long-term relapse arises more frequently in patients in whom a partial hormone control is maintained, seems to support this finding, albeit the presence of 18 ER-negative (ER-) cases in our study. However, this apparent contradictory observation could be explained by the fact that 12 of our patients were in premenopause and that ER-status could have been false ER- results due to the binding of endogenous estradiol to ER.