This is a single arm, pilot, prospective study to evaluate the safety of partial breast irradiation in women who undergo breast conserving surgery without sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND). Baseline demographic and clinical information will be collected. All patients will complete the Breast Cancer Treatment Outcome Scale (BCTOS-13) questionnaire and the Functional Assessment of Chronic Illness Therapy-Comprehensive Score for financial Toxicity at baseline and at 2 years. All patients are required to have an axillary ultrasound prior to radiation start if this was not obtained pre-operatively.