Radiation Therapy After Mastectomy: Long-Term Results

radiation therapist with linear accelerator cancer treatment

What You Need to Know: After mastectomy and axillary dissection, radiotherapy (RT) reduces both recurrence and breast cancer mortality among women with one to three positive lymph nodes, even when systemic therapy is given.

Background: Radiation therapy after breast removal (mastectomy) for breast cancer has been shown to reduce the risk of recurrence and death from the disease for women with cancer spread to regional lymph nodes. However, the benefit among women who have only one to three positive nodes remains uncertain.

The Study: The authors did a meta–analysis (study of a collection of studies), using individual data for 8135 women randomly assigned to treatment groups (during 1964–86 in 22 trials) of radiotherapy to the chest wall and regional lymph nodes after mastectomy and axillary surgery versus the same surgery but no radiotherapy.

  • Follow–up lasted 10 years for recurrence and to Jan 1, 2009, for mortality.
  • Analyses were stratified by trial, individual follow–up year, age at entry, and pathological nodal status.

Results:

  • 3786 women had axillary dissection to at least level II and had zero, one to three, or four or more positive nodes.
  • All were in trials in which radiotherapy included the chest wall, supraclavicular (above the collarbone) or axilla (underarm area), or both, and internal mammary chain (nodes alongside the sternum, or breast bone.
  • For 700 women with axillary dissection and no positive nodes, radiotherapy had no significant effect on locoregional recurrence (, overall recurrence, or breast cancer mortality.
  • For 1314 women with axillary dissection and one to three positive nodes, radiotherapy reduced locoregional recurrence (2p<0.00001), overall recurrence (RR 0.68, 95% CI 0.57–0.82, 2p=0.00006), and breast cancer mortality (RR 0.80, 95% CI 0.67–0.95, 2p=0.01).

For today’s women, who in many countries are at lower risk of recurrence, absolute gains might be smaller but proportional gains might be larger because of more effective radiotherapy. This study adds to the evidence pointing to the value of radiation therapy for women found to have node involvement after surgery. I’m Dr. Michael Hunter, and I am proud to help individuals with cancer.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad: Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minute; Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.

Reference: Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality: meta-analysis of individual patient data for 8135 women in 22 randomized trials. The Lancet, 03/25/2014

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understandcancerin60minutes

Harvard AB Yale MD UPenn Radiation Oncology Radiation Oncologist, Seattle area

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