Benign and low-grade fibroepithelial neoplasms of the breast have low recurrence rate after positive surgical margins

Abstract

Breast phyllodes tumors are uncommon fibroepithelial neoplasms with a range of histologic features. Surgical excision is the primary management, but the need for excision to negative margins in benign and borderline phyllodes tumors is unclear. Here, we review the surgical management patterns and outcomes of 90 patients with benign and low-grade fibroepithelial lesions of the breast treated at our institution, including 19 borderline phyllodes tumors, 52 benign phyllodes tumors, and 19 representative neoplasms with overlapping features of fibroadenoma and benign phyllodes tumors, which were classified as 'fibroadenomas with phyllodal features'. In total, 52 (58%) had positive surgical margins on first excision, and of these 17 (33%) underwent re-excision to achieve negative margins. Residual tumor was identified in three (18%) re-excisions. Patients with fibroadenoma with phyllodal features were more likely to have a positive surgical margin than with benign phyllodes tumors or borderline phyllodes tumors (89 vs 49%, P = 0.0015), and were less likely to undergo re-excision for positive margins (12 vs 43%, P = 0.031). In total, there were three recurrences (3%), with one per fibroadenoma with phyllodal features, benign phyllodes tumor, and borderline phyllodes tumor. There was no statistically significant difference in recurrence rates between patients with positive or negative margins, or between patients with positive margin with or without re-excision. The extent of the positive margin did not predict recurrence. In conclusion, the recurrence rate of benign and low-grade fibroepithelial lesions is low and not associated with the original margin status. Patients with fibroadenomas with phyllodal features, benign phyllodes tumors, or selected borderline phyllodes tumors and positive margins on initial excision may be managed conservatively, with close follow-up and timely re-excision of any potential recurrence.

Fibroepithelial lesions of the breast: a comprehensive morphological and outcome analysis of a large series

“…Moreover, in our study none of the 63 shelled out fibroepithelial lesions resulted in recurrence. The results of our study suggest that atypical fibroadenoma with ink on tumor do not require re-excision and, similarly to other authors [2,5,6], that narrow excision appears to be an adequate treatment for benign phyllodes tumors.…”

“…Most authors agree that margin status is a significant factor predictive of local recurrence [1,2,4,9,10]. There are however different definitions of a positive margin: "ink on tumor" vs. <0.1 mm vs. <1 mm [2,5]. Even with an approach that only "ink on tumor" constitutes a positive margin there are cases with equivocal margin status.…”

“…The challenges in assessing the clinical significance of these characteristics across studies are their inconsistent definitions and lack of a centralized pathology review process. Moreover, the validity of obtaining cm clear margin for benign phyllodes tumors, which often results in suboptimal cosmetic outcome, has been recently challenged [5][6][7].…”

Phyllodes Tumor of the Breast: Histopathologic Features, Differential Diagnosis, and Molecular/Genetic Updates

“…In addition, studies have shown that expectant management towards benign PTs excised without clear margins may be an acceptable option, given an overall low local recurrence rate and rare recurrence as a high-grade tumor from a benign PT. 22,23 These findings suggest that distinction between these 2 entities may not be significant. In core biopsies with morphologic features of fibroadenoma and benign PT, a diagnosis of benign fibroepithelial neoplasm is advocated by some authors and recommended by the WHO classification system.…”

Interobserver Variability by Pathologists in the Distinction Between Cellular Fibroadenomas and Phyllodes Tumors

“…5,10 Additionally, unlike for borderline or malignant phyllodes tumors, studies have suggested that additional surgery following a diagnosis of benign phyllodes tumor may not be necessary as recurrence rates were not significantly affected by margin status. 8,11,12 This begs the following question: If the likelihood of recurrence is similar between a cellular fibroadenoma and a benign phyllodes tumor and additional surgery for clear margins may not be beneficial for either, why separate these 2 diagnoses? One possible reason is that there are studies that have identified benign phyllodes tumors recurring as borderline or malignant tumors and there are rare reports of benign phyllodes tumors metasta-sizing.…”