Is the extent of surgical resection important in patient outcome in benign and borderline phyllodes tumors of the breast?

Background/aim: Phyllodes tumors (PTs) of the breast are rare, and their diagnosis and treatment remain controversial. This retrospective study aims to examine the clinical outcome of benign and borderline PTs, according to the surgical margins. Materials and methods: We examined the medical records of 122 patients in our clinic, who had histologically confirmed benign and borderline PTs between 1994 and 2017. Results: The mean age of the patients was 40.6 years (range 18.0-81.0, ±12.1 standard deviation [SD]) and the mean tumor size was 25.8 mm (range 9-65, ±10.3 SD). All patients underwent a breast-conserving procedure and the median follow-up was 51 months. Tumor margins were positive (tumor touching the ink) in 43 patients (35%). Only 16 patients (13%) had margins ≥10 mm. The margins were between 2 and 10 mm in most patients (40%) and ≤1 mm in 12% of the patients. Conclusion: Although no re-excision was performed to obtain grossly clear margins, local recurrence was not observed in any patients. Therefore, revision surgery for close or positive surgical margins for benign and borderline PTs should not be performed as a rule. As most tumors recur within 2 years of diagnosis, we propose a close clinical and imaging follow-up during this period.