Is there a role for adjuvant radiation in phyllodes tumors of the breast?
The role of adjuvant RT after BCT for phyllodes is not well defined, with wide variation in local recurrence reported in literature and practice is not uniform. The risk of local recurrence appears to be a function of the type of phyllodes (malignant vs. benign), size, and margin status (which to some extent are interrelated as hard to get a wide margin for larger tumor). Our approach is if BCT is done with a 1 cm margin, we don't treat with adjuvant RT, as the risk of LR is close to 10 percent or less. If a wide margin is not attainable and the patient desires BCT, then consider RT. Also, if there is recurrent disease after initial surgery, we do favor adjuvant RT. The only prospective study showing possible efficacy of RT is a single-arm study from Dartmouth.
Barth Jr. et al., PMID 19424757
After the mastectomy, we consider RT for close/ positive margin or large tumor (more than 10cm) based on data from California showing 15% local recurrence.