Identifying The Surgical Cavity Following Oncoplastic Breast Surgery.

81 Background: Oncoplastic surgery (OPS) has improved outcomes for partial mastectomy. However, tissue rearrangement poses challenges in the post-operative management of these patients. In most cases, these patients will require post-operative radiotherapy. Accurately visualizing the surgical cavity can be particularly troublesome in patients who have oncoplastic closure of the resection cavity. Recent advances have made it feasible to perform external beam radiation using advanced methods, but these are not commonly used for breast cancer. This is due to the difficulty in identifying the exact area of the surgical site. In this series of patients, a novel method for marking the surgical site when using oncoplastic techniques was evaluated.65 patients had a 3-D tissue marker implanted at the time of lumpectomy. All patients were candidates for partial mastectomy and local breast reconstruction using OPS. Post-operative treatment plans for radiation and/or adjuvant chemotherapy were completed. Patients were evaluated with standard breast imaging methods for treatment planning.The marker was easily identified and clearly delineated within the lumpectomy cavity. It provided 3-D characterization of the borders surrounding the cavity, and was easily distinguished from seroma and other tissue changes. Respiratory motion was easily tracked using the device making it possible to use IMRT and accelerated protocols. Use of the marker resulted in treatment volumes that were reduced by an average of 50% when compared to standard methods. In appropriate patients when the marker facilitated an accelerated protocol, total treatment time was decreased to 5-7 days. No complications were reported, and overall patient outcomes were excellent.This novel 3-D marker was consistently visualized without difficulty, was readily incorporated into standard practices and had appreciable benefits when designing optimal treatment plans. Its unique features were helpful in all cases, but particularly useful when using oncoplastic techniques to reconstruct the breast with local tissue flaps.