Benign phyllodes tumours of the breast: (Over) treatment of margins - A literature review

Abstract

Background: Phyllodes tumours form a small group of fibroepithelial breast lesions (2-3%). They are classified as benign, borderline, or malignant. (1). Benign phyllodes tumours are the largest subgroup of phyllodes tumours (50-80%), (2) A margin of 1 cm has been suggested as standard of care for all groups of phyllodes tumours.^3-6 METHODS: We performed a literature review from January 2009 to April 2016 including the non-English literature. We compared studies taking a 1 mm margin, 10 mm margin and studies with focal margin involvement.

Results: We included 12 studies with overall 1702 patients. The range of therapeutic margins differed widely between studies. There is no consensus between studies what constitutes a clear or involved margin. There was a high percentage of margin involvement for benign phyllodes tumours (7.6-43.7%). Despite these inconsistencies, the recurrence rate after excision of benign phyllodes tumours was low in most studies (112 recurrences of 1052 benign phyllodes tumours - 11%; range 0-43%). There is no difference of the recurrence rate between studies aiming for a 10 mm margin (7.9%) compared to a 1 mm margin (5.7%) (p 0.124). The recurrence rate increases when there are tumour cells at the margin (12.9%) (p 0.006).

Conclusion: There is no difference in recurrence rates between a 1 and a 10 mm margin. 1 mm is an acceptable margin for benign phyllodes tumours. The recurrence rate increases if there is focal margin involvement.

Keywords: Benign; Margins; Overtreatment; Phyllodes tumours; Recurrence.