The Society of Surgical Oncology (SSO)/American Society for Radiation Oncology (ASTRO) guideline on surgical margins for breast-conserving surgery with whole-breast irradiation in stage I and II invasive breast cancer was considered for endorsement.

The American Society of Clinical Oncology (ASCO) has a policy and set of procedures for endorsing practice guidelines developed by other organizations. ASCO staff reviewed the SSO/ASTRO guideline for developmental rigor; an ASCO ad hoc review panel of experts reviewed the guideline content.

The ASCO ad hoc guideline review panel concurred that the recommendations are clear, thorough, and based on the most relevant scientific evidence in this content area and that they present options acceptable to patients. According to the SSO/ASTRO guideline, the use of no ink on tumor (ie, no cancer cells adjacent to any inked edge/surface of specimen) as the standard for an adequate margin in invasive cancer in the era of multidisciplinary therapy is associated with low rates of ipsilateral breast tumor recurrence and has the potential to decrease re-excision rates, improve cosmetic outcomes, and decrease health care costs.

The ASCO review panel endorses the SSO/ASTRO recommendations with qualifications, as follows. The panel reinforces and amplifies the guideline authors' call for the monitoring of outcomes of the guideline at the institutional level, as institutions transition to adopting the SSO/ASTRO recommendations; would place greater emphasis on the importance of postlumpectomy mammography for cases involving microcalcifications; and calls for flexibility in the application of the guideline in light of the generally weak evidence supporting the recommendations.