ABSTRACT
BACKGROUND: Malignant phyllodes tumor (MPT) is a rare but aggressive breast malignancy. The aim of this study was to evaluate parameters that influence outcome in patients with MPT. METHODS: Fifty women were diagnosed with MPT of the breast and treated between August 1971 and July 2000. All medical records were reviewed retrospectively. The Cox regression model was used for multivariate analysis. RESULTS: Tumors were classified as borderline (6%), low grade (32%), or high grade (62%). The median patient age was 46 years (range, 14-77 years). The median tumor diameter was 3.5 cm (range, 1.5-18 cm). Twenty-two patients had wide local excision (WLE), and 28 patients had mastectomy. The median follow-up was 91 months (range, 12-360 months). Local recurrence (LR) occurred in 16 patients (32%) an average of 26 months after surgery (median, 17 months; range, 3-72 months). Distant metastasis occurred in 13 patients (26%) at an average of 53.4 months (median, 36 months; range, 4-177 months). Sixteen (32%) patients have died of their disease. LR was significantly increased with stromal overgrowth (P < .0001), large tumor size (P = .0177), and surgical margins <1 cm (P = .0120), but not with WLE (P = .5099). Stromal overgrowth was the only independent variable predictive of systemic metastasis (P < .0001) and patient survival (P < .0001). CONCLUSIONS: Stromal overgrowth in MPT carries a grave prognosis. Close surgical margins and large tumor size, but not type of operation, significantly increased LR. Either WLE with adequate margins or mastectomy is an appropriate treatment for patients with MPT.
