rads/chemo for phylloides breast cancer ?

I had a lumpectomy to remove an intermediate-grade malignant phylloides tumor (5.5 cm) almost a year ago. Although I am under close surveillance by oncologist & surgeon, I am still confused about treatment options. I have read where some women receive chemo or rad., but most are treated with just surgery. Because this cancer is so rare, I'm afraid that maybe I am not taking every possible precaution. Any answers?

[CCF-RN,MSN-JS]

Dear Phyl,
The term phyllodes tumor includes a group of lesions of varying malignant potential ranging from completely benign (non-cancerous) to fully malignant sarcomas.  The classification of phyllodes tumors are based on various pathologic findings.   The usual treatment of this type of tumor is with surgery.  If other treatment is recommended such as radiation or chemotherapy it is based on the guidelines for treating sarcomas.   These guidelines, for sarcomas, take into account the margin of tumor free tissue removed at surgery, the grading of tumor by the pathologist, and if there is any concern that there may be spread of the tumor.  If there is concern that there might be microscopic tumor left behind radiation therapy may be recommended.  The use of adjuvant chemotherapy  (chemotherapy given after surgery when all visible and known cancer has been removed by surgery) with sarcomas is not fully established and is currently being studied in clinical trials.