3 Intraoperative Radiotherapy: Alive and Well in the Bronx

3 Intraoperative Radiotherapy: Alive and Well in the Bronx

Background/Significance

Partial breast irradiation (PBI) is an attractive option for women with early-stage breast cancer, with equivalent local control rates to whole breast irradiation (WBI). Intraoperative radiotherapy (IORT) is one method of PBI that allows women to complete adjuvant radiotherapy at the time of breast conserving surgery (BCS). In this current study, we seek to evaluate outcomes of women treated with IORT at our institution in the Bronx, New York.

Materials and Methods

This is a single-center, prospective, observational, institutional review-board–approved registry trial of patients treated with IORT using the Intrabeamsystem from January 2018 to January 2024. Eligible patients included women aged 45 years and older who were candidates for BCS with estrogen receptor–positive, cT1 to 2N0 invasive ductal carcinoma, or grade 1 to 2 ductal carcinoma in-situ (DCIS). Exclusion criteria included known BRCA mutation, neoadjuvant chemotherapy, or multicentric disease. Following BCS, patients received a single dose of 20 Gy to the lumpectomy cavity surface with 50kVp x-rays. Those with high-risk features on final pathology—positive margins with disease on re-excision, positive lymph nodes, tumor size > 3.5 cm or high-grade DCIS— were recommended adjuvant WBI. The primary outcome was locoregional recurrence. Secondary outcomes were overall survival and wound-healing complications.

Results

Between January 2018 and January 2024, 257 women were treated with IORT. The median age was 65.8 years, and most patients (76.7%) identified as non-White. Ten patients were treated with bilateral breast IORT, equating to 267 treated lumpectomy cavities. The majority of the 267 treated tumors were pathologically T1 (n = 197, 73.8%), followed by Tis (n = 37, 13.9%), T2 (n = 31, 11.6%), and T0 (n = 1, 0.4%). Forty-three patients (16.6%) were recommended adjuvant WBI due to high-risk pathology, 37 (86.0%) of whom proceeded.

Median follow-up was 3.2 years (range, 0.4-78 months), during which 6 patients had biopsy-proven ipsilateral breast tumor recurrences, yielding a recurrence rate of 2.2%. Overall survival was 98%, and 10 patients (3.9%) had wound-healing complications.

Conclusion

In our cohort of primarily minority patients, IORT demonstrated a 97.8% locoregional control rate and spared 83.4% of women from the added physical and financial toxicity of WBI. IORT may serve as an economical and safe alternative for women seeking more personalized breast cancer treatment and with limited resources for longer radiotherapy regimens.