How Wide Should Margins Be for Phyllodes Tumors of the Breast?

The surgical management of phyllodes tumors (PTs) is still controversial. Some studies have suggested surgical margins ≥1 cm, but recent studies suggested that negative margins could be appropriate regardless of their width. To evaluate recurrence rates of PTs following surgery according to margins. Retrospective study of women who attended a tertiary breast cancer reference center between 1998 and 2010: 142 patients with a PT diagnosis, either at minimally invasive breast biopsy or at surgery, were identified. Clinical, pathologic and follow-up characteristics were assessed. Among 140 patients who underwent surgery, 64.3% of biopsies accurately predicted the final PT diagnosis at surgery. Forty-two (42/87, 48.3%) PTs had positive margins. Twenty-one (21/42, 50.0%) patients had a surgical revision of margins. Only one (1/42, 2.4%) had margins greater or equal to 1 cm. After a median follow-up of 1.29 years in benign PTs, 4.99 years in borderline PTs, and 5.42 years in malignant PTs, there were five local recurrences, three in originally benign PTs and two in borderline PTs. All were managed with surgery. Four had initial margins ≤1 mm. One patient with borderline PT had a local recurrence and later progressed to regional recurrence and metastasis. Free surgical margins are necessary to treat PT, and margins of at least 1 mm might be sufficient to prevent recurrence. Core needle biopsy might not be the best diagnostic tool for PTs.