ASCO Recommends Tamoxifen for up to 10 Years

Harold Burstein, MD, PhD
Harold Burstein, MD, PhD

Women with hormone receptor-positive (HR+) breast cancer should be given the option to have adjuvant hormonal therapy for as long as 10 years, according to new guidelines issued today by the American Society of Clinical Oncology (ASCO).

The updated guidelines reflect results from several large studies that showed women who took tamoxifen for 10 years had a lower risk of recurrence and a “survival advantage,” compared to women who took the drug for only five years.

In a press release issued by ASCO, Harold J. Burstein, MD, PhD, a breast oncologist with the Susan F. Smith Center for Women’s Cancers at Dana-Farber, explained “tamoxifen taken for five years has been the standard adjuvant hormonal treatment for decades, but we now have evidence to recommend up to 10 years of tamoxifen for women with hormone receptor-positive breast cancer.” Burstein is co-chair of ASCO’s Expert Panel that wrote the guideline update.

The update applies to pre-/peri- and post-menopausal with HR+ breast cancer. However, the guidelines also state that post-menopausal women who have completed five years of tamoxifen should have the option to continue another five years of treatment with either tamoxifen or an aromatase inhibitor.

Before starting any treatment, Burstein notes that women should discuss with their physician the potential risks and benefits of adjuvant hormonal therapy for extended periods of time.

For more information on breast cancer treatment, visit the Susan F. Smith Center Breast Oncology Program website. 

15 thoughts on “ASCO Recommends Tamoxifen for up to 10 Years”

  1. You fail to mention the risk of taking Tamoxifen. My mother died after two breast cancer survivals from uterine cancer. She was on Tamoxifen for 5 years. My 55 year old sister-in-law one year after lumpectomy and radiation and the start of Tamoxifen therapy was diagnosed with uterine cancer. The uterine cancer killed my mother, thankfully after my sister-in-law had her hysterectomy there has been no recurrence. Sorry Doc, but I don’t trust Tamoxifen at all.

    • Dear Kathy —

      Thank you for your question and for reading Insight. This recommendation applies to use of adjuvant endocrine therapy for women with stages I-III hormone receptor positive breast cancer.

  2. I had stage 0 DCIS. It was so small, it was called a biopsy instead of lumpectomy. It was hormone receptor positive. My sister had DCIS and mastectomies for both breasts, 5 years apart. My surgeon recommends Tamoxifen. Is it worth the risk?

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