Is Surgical Excision Necessary for a Benign Phyllodes Tumor of the Breast Diagnosed and Excised by Ultrasound-guided Vacuum-assisted Biopsy Device (Mammotome)?

ABSTRACT

PURPOSE: Phyllodes tumors are characterized by a double-layered epithelial component arranged in cleft-like ducts surrounded by a hypercellular spindle-celled stroma. Currently, phyllodes tumors are classified as benign, borderline, or malignant based on microscopic features. The relatively high rate of recurrence is an unsolved management problem. If a malignant phllodes tumor is treated inadequately, it may show a propensity for rapid growth and metastatic spread. However, benign phyllodes tumor are often indistinguishable from fibroadenoma, and can be cured by local surgery. Percutaneous removal of benign breast tumors using the Mammotome system has recently been regarded as a feasible, safe method without serious complications. The Mammotome system has an expanding role in the surgical treatment of benign breast disease, and may further extend its role to the excision of small malignant lesions. The aim of this study was to evaluate the efficacy and the safety of the Mammotome biopsy device in the treatment of benign phyllodes tumor, and to identify whether surgical excision is necessary for benign phyllodes tumors diagnosed and excised by Mammotome. METHODS: From Jan. 2003 to Feb. 2007, a total of 2,751 US- guided mammotome excisions were performed in 2,226 patients at Kangnam Cha hospital. Out of 2,751 lesions, 30 lesions were proved to be benign phyllodes tumors. All lesions were removed using an 8-gauge probe without any residual lesions. Ultrasonographic follow-up was performed at a 3- to 6-month interval to assess recurrence. The mean follow-up period was 33.2 months (max, 51 months; min, 2 months). RESULTS: The mean patient age was 31.4 years. The average size of the lesion was 1.5 cm (SD+0.43 cm). The majority of lesions, 73.3% (22 cases), were palpable, and 26.7% (8 cases) were nonpalpable. Twenty-two lesions (73.8%) were classified as BIRADS category 3, eight lesions (26.7%) were classified as category 4A by ultrasound. During the follow-up period, local recurrence developed in only one patient, making the local recurrence rate 3.3%. No distant metastasis was observed. CONCLUSION: Benign phyllodes tumors found on mammotome excision may not require surgical reexcision if surgeons are sure that the targeted lesions were excised completely and the follow-up ultrasound does not show any residual lesions, especially in small phyllodes tumors, the greatest dimension of which is less than 3 cm.