Subjects who join the study will receive a shortened course of radiation treatment that will last approximately four (4) weeks, instead of the traditional six (6) week course that women have typically received in this situation. The shorter course subjects will receive is designed in a way that it is thought to be equivalent to the longer course. This shorter course has already been shown to be very safe and effective when treating breast cancer in the breast tissue only. However, because cancer cells were found in the lymph nodes that drain their breast, subjects require radiation to a larger area of their chest, armpit, and shoulder than has been completely tested with this experimental dose.