Interplay of Oncoplastic Reconstruction and Adjuvant Radiation Therapy in Breast Cancer.

ABSTRACT

Purpose: Oncoplastic breast surgery (OBS) combines breast cancer tumor removal with the cosmetic benefits of plastic surgery at the time of breast-conserving surgery. Potential advantages of OBS include wider surgical margins around the tumor bed, while the natural shape and appearance of the breast are maintained more than standard lumpectomy procedures. However, limited information is available regarding the potential effect on adjuvant radiation treatment planning. Materials and Methods: Women with localized breast cancer undergoing lumpectomy with immediate OBS and adjuvant radiation therapy between 2014 and 2019 were reviewed. OBS was performed using volume displacement techniques and patients received whole-breast irradiation with 3-dimensional conformal radiation therapy. Results: Volume of additional ipsilateral breast tissue removed during OBS ranged from 21 to 2086 cm3 (median, 304 cm3), 29% of patients had >500 cm3 of tissue removed. Surgical margins were positive in 12.5% and were not affected by volume of breast tissue removed (445 vs 439 cm3). Patients with surgical clips more often received a lumpectomy bed boost (75.9% vs 50.0%), boost volumes were on average 157 cm3 with clips versus 205 cm3 without clips. Mean V105 was comparable in patients with >500 cm3 tissue removed and irradiated breast volume >1000 cm3, while higher absolute volumes were found in patients with >26 cm posterior separation (58.0 cm3 vs 102.7 cm3; P = .07). No meaningful difference was observed in Dmax or radiation coverage (95% of the volume receiving 95% of the prescription dose) for patients with >26 cm posterior separation, >500 cm3 of breast tissue removed, or irradiated breast volume >1000 cm3. Conclusions: Radiation dosimetry plans for patients undergoing oncoplastic surgery were acceptable and no significant radiation or surgical advantage was gained in patients with more tissue removed. Our study stresses the importance of clear communication between surgeons and radiation oncologists about sufficient marking of the lumpectomy cavity, using practices that minimize the need for re-excisions and minimize lumpectomy cavity disruption during rearrangement.