ASCO Updates Guidelines on Radiation After Mastectomy

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The American Society of Clinical Oncology (ASCO), in conjunction with the American Society for Radiation Oncology and the Society of Surgical Oncology, has put out updated guidelines on using radiation therapy after mastectomy.

The guidelines were published online on Sept. 19, 2016 by the Journal of Clinical Oncology. Read the abstract of “Postmastectomy Radiotherapy: An American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology Focused Guideline Update.”

ASCO is a national organization of oncologists and other cancer care providers. ASCO guidelines give doctors recommendations for treatments and testing that are supported by much credible research and experience.

Cliff Hudis, M.D., of the Memorial Sloan-Kettering Cancer Center, and George Sledge, M.D., of the Indiana University Simon Cancer Center, are among the ASCO experts who updated the guidelines. Both are members of the Professional Advisory Board.

Radiation isn’t given routinely after mastectomy, but it is recommended when the cancer:

  • is larger than 5 cm (about 2 inches)
  • has spread to four or more lymph nodes (called positive or involved nodes)
  • has positive margins (cancer is present at the edge of the biopsy specimen)
  • has spread to the skin

The updated ASCO guidelines offer doctors advice on which women should get radiation after mastectomy.

The guidelines recommend:

  • Radiation after mastectomy reduces the risk of recurrence in women diagnosed with breast cancers that are small (stage T1 or T2) with 1 to 3 positive lymph nodes who have had axillary node surgery. Still, some of these women have such a low risk of recurrence that the side effects of radiation outweigh its benefits. For this group of women, the guidelines recommend that doctors consider factors that could decrease the risk of recurrence or increase the risk of radiation side effects, including:
    • being older than 45
    • other medical conditions that could reduce a woman’s life expectancy
    • other medical conditions that could increase the risk of side effects
    • having only 1 positive lymph node
  • Because of all these factors that can influence the benefits of radiation after mastectomy, decisions about radiation after mastectomy should be made after all a woman’s healthcare providers discuss the matter.
  • The decision to have radiation after mastectomy also should take into account a woman’s preferences.
  • Women diagnosed with small breast cancers (T1 or T2) with a positive sentinel node biopsy who didn’t have axillary node surgery should have radiation after mastectomy only if there is enough information to justify radiation treatment without knowing if more axillary lymph nodes are positive.
  • Women diagnosed with stage I or stage II breast cancer who have received chemotherapy before mastectomy should have radiation after surgery if there are still positive lymph nodes after the chemotherapy is completed.
  • While anecdotal evidence suggests that women diagnosed with stage I or stage II disease who have no cancer left in the lymph nodes after chemotherapy before surgery (called a pathologic complete response) have a low risk of recurrence and could probably skip radiation after mastectomy, there hasn’t been enough research done for the panel to make this recommendation.
  • Women diagnosed with small breast cancers (T1 and T2) with 1 to 3 positive lymph nodes should have radiation to both the internal mammary lymph nodes and the supraclavicular-axillary apical lymph nodes, as well as to the chest wall or reconstructed breast. Internal mammary lymph nodes are the lymph nodes underneath the chest wall. The supraclavicular-axillary apical lymph nodes are the nodes around your collar bone.

"We still don't have a single, validated formula that can determine who needs [postmastectomy radiation therapy], but we hope that the research evidence summarized in this guideline update will help doctors and patients make more informed decisions," said expert panel co-chair Stephen B. Edge, M.D., of the Roswell Park Cancer Institute in Buffalo, N.Y. "We also hope that this publication will spur more research into patient and tumor characteristics that predict risk of recurrence after mastectomy."

If you’ll be having mastectomy to remove breast cancer and are making decisions about radiation after surgery, you may want to ask your doctor about these updated guidelines.

For more information on radiation, including types of radiation and how to manage side effects, visit the Radiation Therapy pages.

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