Local-regional radiation therapy after breast reconstruction: what is the appropriate target volume? A case-control study of patients treated with electron arc radiotherapy and review of the literature.

The oncologic safety and cosmetic outcome of immediate breast reconstruction in breast cancer patients requiring radiation therapy remains ill-defined. Between 1980 and 1998, 18 patients were treated at the University of Utah Medical Center with mastectomy, immediate breast reconstruction, and adjuvant radiation therapy delivered via an electron arc technique. A case-control study was performed matching reconstructed patients in a 1:2 ratio with patients undergoing mastectomy without reconstruction, using number of lymph nodes and tumor size. Median follow-up was 61 months for the reconstructed group. Five-year local-regional control, disease-free survival, and overall survival rates were 87%, 58%, and 74% respectively in the reconstructed group, versus 88%, 57%, and 67% respectively in the matched control group. Cosmesis was good/excellent in 11 of 13 living patients (85%). Significant capsular contraction occurred in 18% of prosthetic reconstruction patients, and revisional surgery was required in 24% of prosthetic reconstruction patients. Utilizing the electron arc technique, the median radiation dose to the chest wall at the midlevel of the ribs was 20% of the prescribed dose, and no patient failed deep to the implant. These results suggest that in appropriately selected patients, structures deep to the reconstruction are not at high risk for local-regional recurrence, and immediate breast reconstruction yields comparable local-regional control, disease-free survival, and overall survival rates to nonreconstructed patients, with acceptable cosmetic results.