Background: Phyllodes tumor is rare fibroepithelial lesion of breast tumor. The main stay treatment is surgery. Although surgery has an adequate surgical margin, the tumor has a tendency to recur locally and occasionally to metastasis.

Objective: To determine parameters that influence recurrence in this uncommon neoplasm.

Material and Method: Data from Ramathibodi Hospital since 1 January 2000 to 31 December 2016 were reviewed retrospectively. 168 patients were newly diagnosed with phyllodes tumors at the Ramathibodi Hospital. We reviewed and analyzed factorsfor recurrence of phyllode tumors after surgery.

Results: The median age of the patients was 43.65 years, ranging from 16 to 66 years. The mean of the tumor size was 4.92 cm, ranging from 0.5 to 32 cm. Based on the criteria proposed by WHO, 107 cases were benign tumors (63.69%), 39 borderline tumors (23.21%), and 21 malignant tumors (12.5%). The median duration of follow-up was 11.92 months that ranged from 3.07 to 62.30 months. Of the 168 cases, 8 (4.76%) patients had recurrence. The mean age of these patients was 46.37 years, and the mean follow-up was 40.02 months. The mean time to recurrence was 17.47 months, with a median of 11.92 months, and ranged of 0.3.07 to 62.30 months. Incidence rate of recurrence tumors was 2.43% and the median follow-up time to recurrence was 34.07 months (95% CI = 21.83 to 30.10). The event free probability of all patient was 5.72% and 50% median time to recurrence was 10.77 month (95% CI = 18.5 to 28.73). Factors of recurrence in the present study were histology (p<0.001) and tumor size (p<0.001).

Conclusion: The tumor size and histology of phyllodes were the principal determinants of the recurrence. Complete surgical excision by either wide local excision or mastectomy if necessary is important in the primary surgical treatment of phyllodes tumors.

Keywords: Phyllodes tumor