Mammary phyllodes tumour: a 15-year multicentre clinical review.

AIMS: Phyllodes tumour (PT) is an uncommon fibroepithelial tumour of the breast. It has a spectrum of aggressiveness in biological behaviour with chance of local recurrence and, occasionally, metastasis.

METHODS: A 15-year retrospective review from a multicentre database in Hong Kong was performed.

RESULTS: Clinical and pathological records of 465 patients with 469 PTs between 1998 and 2014 were reviewed. Median age of occurrence was 44 years (range 12-86 years). 281 (59.9%) PTs were benign, 124 (26.4%) were borderline and 64 (13.6%) were malignant. About half of all PTs (239, 51.5%) were between 2 and 5 cm while another 186 (40.1%) were >5 cm in size. Most PT (84.6%) were radiologically benign. Breast-conserving surgery (BCS) was feasible in 384 (82%) patients, whereas 84 (18%) patients had mastectomy. Multivariate analysis found that positive surgical margin (P<0.001) and BCS (P<0.001) were the only significant risk factors for local recurrence, while large tumour size (P=0.008) and malignant PT histotype (P<0.001) were the only significant risk factors for metastasis. Long-term prognosis of benign and borderline PT was excellent. After median follow-up interval of 85 months (range 12-180 months), the disease-specific survival of benign, borderline and malignant PT were 99.6%, 100% and 90.6%, respectively.

CONCLUSIONS: Local recurrence of PTs occurs irrespective of the tumour grade. Surgical margin is the only amendable factor to reduce the chance of recurrence.