The American Society for Radiation Oncology and the Society of Surgical Oncology have announced the publication of the consensus guideline on margins for breast-conserving surgery with whole-breast irradiation in stage I and stage II invasive breast cancer.
In addition to determining the ideal margin width that minimizes the risk of ipsilateral breast tumor recurrence, the guideline outlines an evidence-based surgical treatment path that could reduce unnecessary surgery for patients.
Society of Surgical Oncology—American Society for Radiation Oncology Consensus Guideline on Margins for Breast-Conserving Surgery With Whole-Breast Irradiation in Stages I and II Invasive Breast Cancer applies the results of a meta-analysis of margin width and ipsilateral breast tumor recurrence from a systematic review of 33 research studies from MEDLINE and evidence-based medicine published from 1965 to January 2013.
The included studies encompassed 28,162 patients with stage I or II invasive breast cancer who were treated with whole-breast irradiation and with a minimum median follow-up time of four years. Patients treated with neoadjuvant chemotherapy or patients with pure ductal carcinoma in situ breast cancer were not included in the research for the guideline.
“A significant portion of breast cancer surgeries in the United States are performed by surgical oncologists, and the definition of an adequate margin has been a major controversy. Therefore, it was only natural that we decided to create a definitive guideline that helps to minimize unnecessary surgery while maintaining the excellent outcomes seen with lumpectomy and radiation therapy,” Monica Morrow, MD, Society of Surgical Oncology immediate past president, breast cancer surgeon and chief of breast surgery at Memorial Sloan-Kettering Cancer Center, said in a press release. “We are proud to provide this pivotal document to the oncology community, which will improve the lives and treatment of patients touched by this disease.”
In addition, the American Society of Breast Surgeons and ASCO both endorsed the guideline.
The consensus guideline includes eight clinical practice recommendations:
- Positive margins, defined as ink on invasive cancer or ductal carcinoma in situ, are associated with at least a two-fold increase in ipsilateral breast tumor recurrence. This increased risk is not nullified by delivery of a boost, delivery of systemic therapy or favorable biology;
- Negative margins (no ink on tumor) optimize ipsilateral breast tumor recurrence. Wider margin widths do not significantly lower this risk;
- The rates of ipsilateral breast tumor recurrence are reduced with the use of systemic therapy. In the event that a patient does not receive adjuvant systemic therapy, there is no evidence suggesting that margins wider than no ink on tumor are needed;
- Margins wider than no ink on tumor are not indicated based on biologic subtype;
- The choice of whole-breast irradiation delivery technique, fractionation and boost dose should not be dependent on margin width;
- Wider negative margins than no ink on tumor are not indicated for invasive lobular cancer. Classic lobular carcinoma in situ at the margin is not an indication for re-excision.
- Young age (≤40 years) is associated with both an increased risk of ipsilateral breast tumor recurrence after breast-conserving therapy and an increased risk of local relapse on the chest wall after mastectomy and is more frequently associated with adverse biologic and pathologic features. There is no evidence that increased margin width nullifies the increased risk of ipsilateral breast tumor recurrence in young patients; and
- An extensive intraductal component identifies patients who may have a large residual ductal carcinoma in situ burden after lumpectomy. There is no evidence of an association between increased risk of ipsilateral breast tumor recurrence and extensive intraductal component when margins are negative.
“Our hope is that this guideline will ultimately lead to significant reductions in the high re-excision rate for women with early-stage breast cancer undergoing breast-conserving surgery,” said Meena S. Moran, MD, associate professor of the department of therapeutic radiology at Yale School of Medicine. “Based on the consensus panel’s extensive review of the literature, the vast majority of re-excisions are unnecessary because disease control in the breast is excellent for women with early-stage disease when radiation and hormonal therapy and/or chemotherapy are added to a women’s treatment plan.”
The consensus guideline is available open access online as a PDF document at www.redjournal.org, www.annsugoncol.org and http://jco.ascopubs.org, and will be published in:
- the March 1 print issue of the International Journal of Radiation Oncology*Biology*Physics;
- the March print issue of Annals of Surgical Oncology; and
- the March 10 issue of the Journal of Clinical Oncology.