Treatment and outcome of cystosarcoma phyllodes in Brunei: a 13-year experience.

Cystosarcoma phyllodes is a rare tumour of the breast whose clinical behaviour does not correlate well with histological findings. The optimal treatment of this tumour remains controversial. A retrospective study on the treatment and outcome of women diagnosed with cystosarcoma phyllodes between 1986 and 1998 in Brunei was undertaken. Twenty-seven women were diagnosed over the 13-year study period. Follow-up was complete in 26 cases. The mean age at diagnosis was 35 years. There were 19 (73%) histologically benign lesions, 3 (12%) borderline lesions and 4 (15%) malignant lesions. The mean follow-up period was 37 months. Four patients (16%) had recurrences after surgery (1 benign, 1 borderline and 2 malignant lesions). Mean time to recurrence was 9 months. Breast-conserving surgery with adequate resection margin is advocated in benign and borderline lesions. For malignant lesions, simple mastectomy without routine axillary dissection is recommended. More research is required to determine the role of adjuvant chemotherapy and radiotherapy in the management of malignant cystosarcoma phyllodes [corrected].