ASCO Releases Guidelines for Bisphosphonates as Adjuvant Therapy

Bone-modifying medicines should be considered for postmenopausal women
Breast Cancer News
September 26, 2017
By: 
Eric Fitzsimmons, Copy Editor and Content Coordinator
Reviewed By: 
Adam Brufsky, MD, PhD

The American Society of Clinicalinfo-icon Oncologyinfo-icon recently published new guidelines for the use of bisphosphonates and other medicines that have been used to improve bone health in treating early-stage breast cancerinfo-icon. The guidelines, published in the Journal of Clinical Oncology, recommend two bisphosphonates that should be considered in treating women with breast cancer who have already gone through menopauseinfo-icon.

Background and Goals

Bisphosphonates are a type of medicineinfo-icon used primarily to protect and repair bones that grow weak when the body stops making the hormoneinfo-icon estrogeninfo-icon. But researchers have recently studied whether these medicines help prevent breast cancer recurrences. In particular, the researchers were interested in whether bisphosphonates help protect women from having breast cancer spread to their bones, the most common location for a metastaticinfo-icon recurrenceinfo-icon.

ASCO, working with Cancer Care Ontario, set up a group to review already-published studies and set guidelines for when and how bisphosphonates and other medicines for bone health should be recommended as part of breast cancer treatment.

Design

Much of the data reviewed by the ASCO and Cancer Care Ontario working group came from an analysis by the Early Breast Cancer Trialists’ Collaborative Group. That analysis included results from 26 trials that enrolled a total of 18,766 women. The ASCO and CCO working group also included results from several other trials that started later than 2008, the cutoff for the EBCTCG analysis, or looked at bone-modifying medicines besides bisphosphonates, the focus of the EBCTCG analysis.

The working group focused on four research questions:

  • Do bisphosphonates or other medicines that affect your bones lower the risk of cancer returning or traveling to other parts of the body, or a person’s risk of dying from any cause?
  • Do bisphosphonates or other bone-health medicines work better or worse in treating certain stages of cancer or subtypes of cancer, or if the woman is pre- or postmenopausalinfo-icon?
  • Do types of bisphosphonates have different side effects and benefits?
  • How should people be given bisphosphonates or other bone-health medicines and what doseinfo-icon should they be given?

Results

After reviewing the data, the group wrote six recommendations for when to use bisphosphonates as breast cancer treatment. The researchers note that their recommendations are based on lower rates of recurrence and death seen in people with early-stage breast cancer:

  • Bisphosphonates should be considered for postmenopausal women who are recommended systemicinfo-icon treatments like chemotherapyinfo-icon and hormonal therapyinfo-icon.
  • Zoledronic acidinfo-icon and clodronateinfo-icon are the recommended bisphosphonates for breast cancer treatment.
  • There are not enough data to recommend denosumabinfo-icon, but promising early results should encourage more research.
  • Recommended doses are
    • 4 milligrams of zoledronic acid given by veininfo-icon every 6 months for 3 to 5 years or
    • 1,600 milligrams of clodronate given daily by mouth for 2 to 3 years
  • These recommendations are for women who have gone through natural menopause or menopause caused by surgeryinfo-icon or ovarian suppressioninfo-icon.
  • A dental exam should be done before starting bisphosphonates

The studies showed that bisphosphonates improved results for all women who already went through menopause and that the improvement was consistent for women with different tumorinfo-icon features and getting different chemotherapy medicines. But the researchers said that improvement overall was small, and how much bisphosphonates will benefit you will depend on your risk of recurrence.

The researchers noted that bisphosphonates should not replace any current anti-cancer treatment. They should be given in addition to any treatment your doctor would already recommend. In the EBCTCG analysis, 83 percent of women given bisphosphonates were also getting chemotherapy.

Getting a dental checkup and completing any dental work before taking a bisphosphonateinfo-icon because they come with a risk of osteonecrosis of the jawinfo-icon, a painful, exposed area of bone in your jaw. Getting an invasive dental procedure while on bisphosphonates puts you at a higher risk of the side effectinfo-icon. You may also have calcium and vitamin D supplements recommended while you are on bisphosphonates to help maintain bone health.

Though the reccomended doses have been proven to be effective, researchers say dose and schedule for these medicines have not yet been found.

What This Means for You

Bisphosphonates could provide another treatment option if you are past menopause and have a high risk of recurrence. These guidelines are the first for bisphosphonates and other medicines that affect your bones to be used as breast cancer treatment and more doctors may more often discuss or recommend the addition of a bisphosphonate to your treatment.

If your doctor does not recommend bisphosphonates for preventing recurrence, but you think you meet the criteria for someone who should consider it, it is OK to ask why. Many factors are considered in deciding your treatments including side effects, risks, benefits and how medicines interact with other treatments you need. Other medicines of this type are being tested in clinical trials. Expect updates to this guideline in coming years.

Dhesy-Thind, S.; Fletcher, G.; Blanchette, P.; et al. Use of Adjuvant Bisphosphonates and Other Bone-Modifying Agents in Breast Cancer: A Cancer Care Ontario and American Society of Clinical Oncology Clinical Practice GuidelineJournal of Clinical Oncology 35, no. 18 (June 2017); doi:10.1200/JCO.2016.70.7257.

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