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Study: Does extending hormonal therapy impact risk of breast cancer recurrence?

Hormonal therapy significantly reduces the risk of recurrence for women with early-stage estrogen receptor-positive breast cancer. Standard hormonal therapy is given for 5 years; extending that therapy for a longer period offers additional protection but has added side effects. This study looked at women who stopped hormonal therapy after 5 years and identified factors that may guide the decision to extend treatment.  (12/21/17)

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Contents

At a glance In-depth
Findings     Limitations         
Clinical trials Resources                 
Questions for your doctor                                         


STUDY AT A GLANCE

This study is about:

  • Identifying which patients with ER-positive breast cancer could safely stop endocrine (hormonal) therapy (thereby avoiding the side effects) after 5 years because their risk for long-term distant recurrence was "so small” 
  • Factors that may influence whether or not to extend hormonal therapy beyond 5 years for women with early-stage estrogen receptor- (ER-) positive breast cancer.

Why is this study important? 

Standard treatment for early-stage breast cancer often includes 5 years of endocrine-based (hormonal) treatments such as tamoxifen or aromatase inhibitors (both are pills that are taken daily). The aim of this study was to learn which patients could stop hormonal therapy after 5 years because their risk of recurrence would be very small. However, this study found that even for women believed to be at low risk of recurrence, breast cancer recurrences continued steadily for up to 20 years after diagnosis. This study identified which features of a patient’s original cancer influence long-term risk of recurrence. These findings may help guide the decision of whether or not to extend standard hormonal therapy beyond 5 years. 

Study findings:

In women diagnosed with early-stage ER-positive breast cancer who stopped endocrine therapy after the standard 5 years of treatment, breast cancer recurrence occurred at a steady rate from 5 to 20 years. Over the study period, risk of recurrence was strongly linked to the original cancer's size and to the number of positive at the time of diagnosis.

  • Among women with early-stage T1(2 cm or less) breast cancer, risk of recurrence was:
    • 13% for those with no positive lymph nodes
    • 20% for those with 1 to 3 positive lymph nodes
    • 34% for those with 4 to 9 positive lymph nodes
  • Among women with early-stage T2 (larger than 2 cm but less than 5 cm) breast cancer, risk of recurrence was:
    • 19% for those with no positive lymph nodes
    • 26% for those with 1 to 3 positive lymph nodes
    • 41% for those with 4 to 9 positive lymph nodes

What does this mean for me?

The results of this study may help identify which early-stage ER-positive breast cancer patients would most benefit from extending hormonal therapy beyond the standard 5 years of treatment. However, the benefits of extending endocrine therapy must be weight against side effects. The findings of this study underline the need to help women who are receiving endocrine therapy to discover whether any side effect symptoms are actually caused or made worse by therapy.

Posted 12/21/17

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Expert Guidelines

In 2019, the American Society of Clinical Oncology (ASCO) published updated guidelines on endocrine treatment (hormonal therapy) for women with breast cancer. The guidelines recommended:

  • Women with node-positive breast cancer should receive extended therapy, including an aromatase inhibitor, for up to a total of 10 years of endocrine treatment.
  • Women with node-negative breast cancer should consider extended therapy for up to a total of 10 years of adjuvant endocrine treatment based on considerations of their risk for recurrence.
  • The decision to extend or not extend hormone therapy should be a shared decision between doctors and patients based on discussions that weighs the benefits of lowering the risk for breast cancer recurrence and preventing second breast cancers versus the negative impact of treatment side effects.

The ASCO Panel notes that the benefits of reduction are small and that a substantial portion of the benefit for extended adjuvant aromatase inhibitor therapy comes from preventing a new breast cancer diagnosis.

Updated: 01/02/2022

Questions To Ask Your Doctor

  • Would I benefit from extending hormonal therapy beyond the standard 5 years?
  • What are the side effects and of hormonal therapies like tamoxifen?
  • What are the side effects and toxicity of aromatase inhibitors?
  • What are the added side effects of extending hormonal therapy beyond 5 years? 

Open Clinical Trials

The following studies are enrolling people with early-stage ER-positive, breast cancer. 

Several other clinical trials for patients with early-stage breast cancer can be found here.

Updated: 02/01/2024

Peer Support

The following organizations offer peer support services for people with or at high risk for breast cancer:

Updated: 05/07/2024

Who covered this study?

NBC News

Breast cancer may return even 20 years later, study finds This article rates 5.0 out of 5 stars

Healthline

Long haul for breast cancer survivors: disease can return after 20 years This article rates 4.0 out of 5 stars

Modern Medicine Network

Risk of breast cancer recurrence can last up to 20 years This article rates 3.5 out of 5 stars

How we rated the media