How is estrogen receptor (ER) or progesterone receptor (PR)–positive breast cancer treated?

Updated: Apr 23, 2020
  • Author: Joseph A Sparano, MD; Chief Editor: John V Kiluk, MD, FACS  more...
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Patients with invasive breast cancer that is estrogen receptor (ER) or progesterone receptor (PR)–positive should be considered for adjuvant endocrine therapy. Options for endocrine therapy in breast cancer patients include the following:

  • Tamoxifen
  • Aromatase inhibitors (AIs)
  • Luteinizing hormone–releasing hormone (LHRH) analogues
  • Oophorectomy may produce additional benefit

Selection considerations are as follows:

  • Selection of agents depends on menopausal status and concern about side-effect profile (eg, thrombosis with tamoxifen, bone loss with AIs)

  • Tamoxifen has been shown to reduce the risk of recurrence by about 40% and the risk of death by about 30%, is effective in both premenopausal and postmenopausal women, and may be used either alone or after chemotherapy [23]

  • Acute toxicities of tamoxifen include hot flushes and gynecologic symptoms; long-term toxicities are thrombosis and uterine cancer

  • AIs are effective for postmenopausal women, reducing the risk of recurrence by approximately 20% compared with tamoxifen [24, 25, 26, 27]

  • Nonsteroidal AIs (anastrozole, letrozole) and steroidal AIs (exemestane) exhibit comparable efficacy and side effects

  • Acute toxicities of AIs include arthralgias, hot flushes, and gynecologic symptoms; osteoporosis is a long-term adverse effect

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