What are the ASCO guidelines on adjuvant endocrine therapy for breast cancer?

Updated: May 21, 2019
  • Author: Erin V Newton, MD; Chief Editor: Neetu Radhakrishnan, MD  more...
  • Print
Answer

Answer

In 2014, the American Society of Clinical Oncology (ASCO) issued an updated clinical practice guideline on adjuvant endocrine therapy for women with hormone receptor–positive breast cancer. The guideline includes the recommendation that women with stage I to III disease consider taking tamoxifen for 10 years. [38, 39]

For pre- or perimenopausal patients, ASCO recommends offering adjuvant endocrine therapy with tamoxifen for 5 years, after which the patient should receive additional therapy based on her menopausal status. If the patient is premenopausal, she should be offered continued tamoxifen for a total duration of 10 years. If the patient is postmenopausal, she should be offered continued tamoxifen for a total duration of 10 years or an aromatase inhibitor for a total duration of up to 10 years of adjuvant endocrine therapy. [38, 39]

A study by the Early Breast Cancer Trialists’ Collaborative Group found that 5 years of adjuvant tamoxifen therapy safely reduces the 15-year risks of breast cancer recurrence and death. [40]

Postmenopausal patients should be offered adjuvant endocrine therapy with one of the following regimens [38, 39] :

  • Tamoxifen for 10 years
  • An aromatase inhibitor for 5 years
  • Tamoxifen for 5 years, then switching to an aromatase inhibitor for up to 5 years
  • Tamoxifen for 2-3 years, then switching to an aromatase inhibitor for up to 5 years

Postmenopausal patients who are intolerant of either tamoxifen or an aromatase inhibitor should be offered an alternative adjuvant endocrine therapy. Patients who have received an aromatase inhibitor but discontinued treatment at less than 5 years may be offered tamoxifen for a total of 5 years. Patients who have received tamoxifen for 2-3 years should be offered an aromatase inhibitor for up to 5 years, for a total duration of up to 7-8 years of adjuvant endocrine therapy. [38, 39]


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!