Radiation therapy (radiotherapy) is a highly targeted and highly effective way to destroy cancer cells in the breast that may stick around after surgery. Despite what many people fear, radiation therapy is relatively easy to tolerate and its side effects are limited to the treated area.
The deciding factors on which women should be prescribed radiation after mastectomy has lead to the release of the following guidelines by The American Society of Clinical Oncology (ASCO), in conjunction with the American Society for Radiation Oncology and the Society of Surgical Oncology.
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:
1. Radiation after mastectomy reduces the risk of recurrence in women diagnosed with breast cancer 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 cancer (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.
If you are making decisions about radiation after surgery, ask your doctor about these updated guidelines.
The guidelines were published online on Sept. 19, 2016 by the Journal of Clinical Oncology.