ARE WIDER MARGINS NEEDED AFTER NEOADJUVANT CHEMOTHERAPY?
Whereas the “no tumor on ink” paradigm has gained considerable traction in breast-conserving surgery (BCS), there is considerably less data on margins in the neoadjuvant chemotherapy (NCT) setting. For the most part, clinical practice in this group of patients has been driven by expert recommendations. The issue is that following NCT, due to intratumoral heterogeneity, up to 40% of cancers shrink with a scattering of residual tumor (Wang et al.). This likely explains the Early Breast Cancer Trialist Collaborative Group (EBCTCG) report of increased risk of local recurrence in the NCT setting. The EBCTCG study reported a 15-year local recurrence rate of 21% after NCT compared to 16% after adjuvant chemotherapy.
A recent retrospective study by Wimmer et al. from Vienna and Linz, Austria, addressed this issue. Four hundred six patients were analyzed. The median age was 51, and the median follow-up was 84 months. Forty-five percent were premenopausal, whereas 55% were postmenopausal. Though 51 patients did not have HER2 determined, the remaining subtypes were as follows: 47% HR pos/HER neg, 29% HR neg/HER2 neg, 14% HR pos/HER2 pos, 10% HR neg/HER2 pos. There was a 12% re-excision rate. A margin width of ≤ 1mm was reported in 18% of patients, >1mm in 70%, and pCR in 12%.
When the authors examined local relapse-free survival (LRFS) and overall survival (OS), they found no significant difference between patients with negative margins and those with no residual disease in the breast. There was a non-significant trend of higher 5-year survival in patients with no residual breast disease (not including the axilla). When the patients were further subdivided into margins ≤ 1mm and > 1mm, there was no significant difference found for either LRFS, OS, or disease-free survival.
In the population studied, clear margins defined by “no tumor on ink” yielded excellent outcomes. There was no difference in local recurrence rates in patients with close or widely clear margins. The study suggests that “no tumor on ink” can be applied safely to patients in the neoadjuvant setting.