The following article features coverage from the San Antonio Breast Cancer Symposium (SABCS) 2017 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Narrower surgical margins do not necessarily imply a reduced risk of ipsilateral breast tumor recurrence (IBTR) for patients undergoing breast-conserving treatment, according to an updated meta-analysis presented at the 2017 San Antonio Breast Cancer Symposium.1

The findings indicate that margin widths of at least 2 mm are associated with a reduced risk of ipsilateral breast failure compared with narrower but uninvolved margins, said study coauthor Frank A. Vicini, MD, FACS, of 21st Century Oncology/Michigan Healthcare Professionals in Farmington Hills, Michigan.

“Limitations of the meta-analysis preclude definitive conclusions regarding appropriate margins,” Dr Vicini said. “Data suggest, however, that having a margin width beyond no tumor-on-ink may further reduce rates of local recurrence.”

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Dr Vicini and colleagues conducted a new meta-analysis including data from 38 studies representing 55,302 patients treated between 1968 and 2010.

For this meta-analysis, the authors used 3 different statistical models. Model 1 was similar to a previous analysis and used dichotomous margin categories (either negative or close/positive margins). Model 2 treated margin width as ranges rather that cutoff thresholds (eg, 0 to 2 mm, 2 to 5 mm, greater than 5 mm). Model 3 was similar to model 2 but used categories of negative, close, or positive margins.

For local recurrence in model 1, benefit to wider margins was observed, with the greatest benefit seen at 1 mm. Similar rates of recurrence were, however, found with all negative margin category criteria, Dr Vicini reported. In multivariate analysis, the only significantly predictive variable was margin status (0, 1, 2, and 5 mm).

Model 2 showed that margin width was the significant variable; only wider margin was associated with “further reduced local recurrence,” Dr Vicini said.

The results of multivariate analysis for model 3, in which margins were categorized as negative, close, or positive, margin status and margin width were significantly associated with local recurrence. That finding was similar to a previous meta-analysis, but “suggests larger margin width may affect local recurrence in multivariate analysis,” Dr Vicini said.

“These findings do not necessarily mean we should change the existing recommendations,” Dr Vicini said.

Read more of Cancer Therapy Advisor‘s coverage of the San Antonio Breast Cancer Symposium (SABCS) 2017 meeting by visiting the conference page.

Reference

  1. Shah C, Verma V, Sayles H, Recht A, Vicini. Appropriate margins for breast conserving surgery in patients with early stage breast cancer: a meta-analysis. Oral presentation at: 2017 San Antonio Breast Cancer Symposium; December 5-9, 2017; San Antonio, TX.