Temporal Trends in the Use of Immediate Oncoplastic Techniques in Women Undergoing Breast Conserving Surgery and Adjuvant Radiation

Abstract

Whole breast irradiation (WBI) is an integral component of breast conservation in the majority of women that undergo lumpectomy for breast cancer. Randomized trials also support the use of a lumpectomy cavity boost to further decrease the risk of in-breast tumor recurrence. Lumpectomy may be accompanied by oncoplastic techniques (OT) in which the breast tissue, sometimes including portions of the lumpectomy cavity , is rearranged in order to provide a more aesthetic appearance of the breast. OT may lead to challenges in identifying the lumpectomy cavity at the time of radiation planning. We set to determine the frequency of OT in our patients undergoing WBI. We hypothesized that the use of OT is increasing over time. We identified all women that underwent curative intent WBI (+/- regional nodal irradiation, RNI) in our department from 1/2013-6/2017. Women treated with partial breast irradiation and women without a primary tumor in the breast were excluded. We defined the modern cohort as women treated from 1/2015-present. The operative report(s) for each patient were individually reviewed to determine whether or not an OT was performed prior to initiation of WBI. Baseline patient and tumor characteristics were collected. The breast clinical target volume (CTV), lumpectomy gross tumor volume (GTV) and lumpectomy CTV were collected from the CT dataset. Our primary aim was to compare the rate of OT in the modern versus the earlier cohort using the chi-square test (p<0.05 considered significant). The Wilcoxon ranked sum test was used to compare differences in median lumpectomy GTV/CTV between the OT and non-OT groups. We identified 920 patients, 586 of which were in the modern cohort. The majority of patients had stage 0-II disease (N=877), a minority received neoadjuvant chemotherapy (N=82), and a minority underwent RNI (N=88). The median WBI dose was 50 Gy (IQR, 42.6-50 Gy) and 70% of patients underwent lumpectomy cavity boost (median dose=10 Gy, IQR=10-12 Gy). A total of 54 patients underwent OT: 37 reduction mammoplasties, 16 parenchymal advancement flaps, and 1 crescent mastopexy. The rate of OT was significantly higher in the modern vs. early cohort: 8.2% (48/586) vs. 1.8% (6/344), p<0.0001. Patients in the OT group vs. non-OT group had numerically larger median lumpectomy GTV [19.3 mL (IQR=12.0-32.6 mL) vs. 17.1 mL (IQR=10.1-28.0 mL), p=0.25] and median lumpectomy CTV [86.8 mL (IQR=52.4-135.5 mL) vs. 74.3 mL (IQR=48.8-112.8 mL), p=0.25]. In summary, we found an increasing rate in the use of OT in women undergoing lumpectomy for breast cancer at our institution. The majority of these women underwent lumpectomy cavity boost, which underscores the importance of radiation techniques that can more accurately target the lumpectomy cavity. These data support the prospective evaluation of an intraoperative radiation therapy boost in women that receive lumpectomy with immediate oncoplastic reconstruction as part of breast conservation.