ESTRO 2024 - Abstract Book

S593

Clinical - Breast

ESTRO 2024

Mastectomy is the current standard treatment for recurrence of breast cancer (BC) or second tumors after previous glandular irradiation. In selected cases of local recurrence (luminal molecular subtype and early stage), breast conserving surgery (BCS) with reirradiation with intraoperative radiation therapy (IORT) in the ipsilateral breast is an emerging treatment alternative.

Material/Methods:

Patients treated with BCS and IORT in our center with a history of previous ipsilateral breast cancer treated with conservative surgery and radiotherapy were analyzed. The Xoft Axxent electronic brachytherapy device was used. Histopathological variables were reviewed. The local recurrence rate, disease progression, overall survival, and toxicity were analyzed.

Results:

21 patients were selected between March 2016 and March 2023. All of them had a history of BCS due to previous breast cancer. The Prescription dose of IORT was 20 Gy in all cases. The histology of local recurrence was invasive ductal carcinoma (IDC) in all patients: 9 Luminal A (42,8%), 11 Luminal B (52,3%) and 1 Triple-negative (4,9%).The median time between both tumors was 11 years (range 1-27). The median follow-up after IORT was 46.7 months. In 38% (8/21) of patients had recurrence was in the same quadrant, and 62% occurred in a different quadrant. The most frequently affected location in both cases was the superior-external quadrant. The most common side effect after IORT was seroma, only 1 required drainage. There was no radiodermatitis equal to or greater than G2. Local recurrence was observed in 1 patient (4.7%), which was performed out of indication due to refusal to mastectomy. Another patient developed a single bone metastasis at L3 where SBRT was performed, currently without progression and under systemic treatment. 100% are alive and under active follow-up.

Conclusion:

In well-selected partial breast irradiation patients with good prognostic profile, IORT as a re-irradiation technique in second-BCS is a well-tolerated option with excellent oncological results in our series. It allows the breast to be preserved avoiding mastectomy, and therefore improving perception of illness and quality of life.

Keywords: IORT, APBI, local recurrence

References:

Montagne L, Gal J, Chand ME, et al. GEC-ESTRO APBI classification as a decision-making tool for the management of 2nd ipsilateral breast tumor event. Breast Cancer Res Treat. 2019;176(1):149-157. doi:10.1007/s10549-019-05221-z

Hannoun-Levi JM, Gal J, Polgar C, et al. Second Conservative Treatment for Local Recurrence Breast Cancer: A GEC ESTRO Oncological Outcome and Prognostic Factor Analysis [published online ahead of print, 2023 Jul 15]. Int J Radiat Oncol Biol Phys. 2023;S0360-3016(23)02194-6. doi:10.1016/j.ijrobp.2023.06.075