ASCO endorses "no ink on tumor" guidelines for breast cancer surgery


An expert review panel from the American Society for Clinical Oncology largely endorsed new guidelines for "no ink on tumor" margins in early breast conservation surgery, while emphasizing the role of post-lumpectomy imaging in patients with microcalcifications and adding several other "minor qualifications."

Published earlier this year, the guidelines from the Society of Surgical Oncology (SSO) and the American Society of Radiation Oncology (ASTRO) focus on stage I and II breast cancer patients who are undergoing lumpectomy with whole-breast radiation. In these patients, a "no ink on tumor" margin "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 guideline’s authors wrote (Ann. Surg. Oncol. 2014;21:704-16). The guidelines mark a step toward consensus on a historically controversial topic. "Widespread adoption of this guideline, which defines a margin as being adequate as long as there is no cancer at the inked lumpectomy surface by microscopic pathology evaluation, will result in fewer re-excision lumpectomies and enhanced cosmesis with breast conserving surgery," said Dr. Lisa Newman.

The recommended margin reflects the current era of treatment, in which better systemic therapies and earlier diagnosis of breast cancer mean that patients may no longer derive extra benefit from thicker or "widely negative" lumpectomy margins, Dr. Newman added in an interview.

Two staff members at ASCO reviewed the guidelines for developmental rigor. The guidelines "scored high (77%) in terms of methodologic quality, with only minor deviations from the ideal," members of the separate ad hoc panel of ASCO experts wrote (J. Clin. Onc. 2014 [doi:10.1200/JCO.2014.55.1572]). But panel members also called for flexibility in applying the guideline, citing the "inherent weaknesses" and "selection bias" of the retrospective, observational studies on which the recommendations were based.

The guidelines provide a framework, but clinical judgment remains important in managing breast-conserving surgery patients, emphasized Dr. Newman, who served as cochair on the ASCO panel that reviewed the guideline and who is a surgical oncologist, professor of surgery, and director of the Breast Care Center for the University of Michigan, Ann Arbor. She said clinicians should carefully evaluate lumpectomy margins, which "can provide important clues regarding the burden of disease in the breast, and the likelihood of successful treatment with lumpectomy and breast radiation."

ASCO panel members also stressed the importance of postsurgical imaging in cases involving microcalcifications. Imaging is important to minimize the risk of leaving pockets of disease in the breast despite achieving microscopically negative margins, Dr. Newman said. Surgeons can work with their colleagues in breast imaging to review microcalcifications and correlate them with pathology findings, she added.

In particular, a lumpectomy specimen that has several close margins and evidence of diffuse disease "may well represent a different category of risk regarding local recurrence, compared to a well defined, unifocal cancer that has a single microscopic focus of cancer abutting one margin," Dr. Newman added. Ideally, surgeons and radiation oncologists should discuss these aspects of cases, and should consider them when counseling patients about outcomes from lumpectomy surgery, she said.

Both ASCO and SSO/ASTRO recommended monitoring outcomes as institutions implement the new margin guidelines. Authors of the ASCO opinion reported having no conflicts of interest.

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