Outcome and predictive factors of local recurrence and distant metastases following primary surgical treatment of high-grade malignant phyllodes tumours of the breast

Aim: High-grade malignant phyllodes tumour (MPT) is a rare but aggressive breast malignancy and forms approximately 25% of all phyllodes tumours. The aim of the study was to determine parameters that influence outcome in high-grade MPT. Methods: This study consisted of 48 women diagnosed with high-grade MPT. All patients were treated primarily with surgery by local excision (LE, margins <1 cm), wide local excision (WLE, margins ≥1 cm) or mastectomy. Coxʹs regression was used for multivariate analysis of the data. Results: The mean patient age was 47 (range 21–85) years and the average tumour size was 7.8 (range 1.5–20) cm. Ten patients were treated with LE, 14 with WLE and 24 with mastectomy. The median follow-up was 9 years (range 5 months–28 years). Local recurrence (LR) occurred in 19 patients (40%) at mean time of 28 (range 5–84) months after primary treatment. Distant metastasis (DM) occurred in 13 (27%) patients at average time of 25.6 (range 6–120) months. LR, subsequent metastatic spread and survival following treatment of MPT were related to tumour size and excision margins, but not to other clinical or histopathological characteristics. Conclusion: Tumour size and surgical margins were found to be the principal determinants of LR and DM. Complete surgical excision, by mastectomy if necessary, is important in the primary surgical treatment of high-grade MPT.