Breast Cancer

SS 23 - Breast 3?- General

160 - Technique and Preliminary Results of a Multi-Center Trial of Intra-Operative Radiation Therapy Using Electronic Brachytherapy at the Time of Breast Conserving Surgery for Early Stage Breast Cancer

Tuesday, October 23
1:20 PM - 1:30 PM
Location: Room 303

Technique and Preliminary Results of a Multi-Center Trial of Intra-Operative Radiation Therapy Using Electronic Brachytherapy at the Time of Breast Conserving Surgery for Early Stage Breast Cancer
A. N. M. Syed; MemorialCare Long Beach Medical Center, Long Beach, CA; Long Beach Memorial Medical Center, Long Beach, CA

Purpose/Objective(s): To describe and report on early experience of a multi-center, non-randomized study of patients treated with a single fraction of intra-operative radiation therapy (IORT) using an electronic high dose rate brachytherapy system following surgical resection of early stage breast cancer.

Materials/Methods: 1174 patients were enrolled between May 2012 and January 2018 by 30 US and International institutions upon meeting the inclusion/exclusion criteria. All patients underwent partial mastectomy and sentinel node biopsy of the axilla. A small shield was placed against the chest wall and a balloon applicator was inserted into the lumpectomy cavity and inflated with saline and skin was temporarily closed over the balloon. Ultrasound was performed to confirm that the balloon surface to skin distance was >1.0 cm. A single fraction of 20 Gy was delivered to the lumpectomy cavity at the balloon applicator surface using the electronic high dose rate brachytherapy system. The mean treatment was 10.5 minutes. After treatment, the balloon was deflated, the shield and the applicator were removed and the skin sutured.

Results: 1174 patients received the prescribed dose of 20 Gy. The median followup from the time of treatment to last followup was 584 days. 839/1174 (72%) patients were “ASTRO suitable” with mean age of 66.9 years and 328/1174 (28%) “ASTRO cautionary/unsuitable” with mean age of 63.61 years. 894 (76%) patients had IDC, 224 (20%) DCIS, 50 (4%) other histology and six patients had unknown histology. 79% of the patients were Caucasian, 6.4% African American and 7.5% Hispanic and 7.1% others. 127/862 (14.8%) patients had T1a, 309/862 (36.5%) T1b and 424/862 (49.4%) T1c. Estrogen receptor was positive in 907 (77.3%) patients, negative in 56 (4.8%) and unknown in 175 (14.9%) of patients and unavailable in 36 (3.1%). Progesterone was positive in 848 (72.2%) of patients, negative in 112 (9.5%) and unknown in 36 (3.1%) of patients. All patients were BRCA negative. 36% of IDC was Grade 1 (well differentiated), 46% Grade 2 (moderately differentiated), 16% had Grade 3 (poorly differentiated) and Grade was not available for 2% in the patients. The DCIS grade was evenly distributed between high, low and intermediate nuclear grade. Grade 3, 4 and 5 adverse events occurred in 37 patients. The most common were seroma (17.4%), erythema (13.4%), induration (12.0%), breast pain (6.1%) and fibrosis (8.6%). A total of 10/1174 (0.85%) had ipsilateral recurrence and 4/1174 (0.34%) developed new primary cancers in the contralateral breast.

Conclusion: IORT using the electronic high dose rate brachytherapy system in the conservative treatment of breast cancer is safe with low morbidity. Preliminary results from this multi-center trial demonstrate that a single fraction of radiation for early stage breast cancer yields excellent local control and cosmesis and low morbidity.

Author Disclosure: A.N. Syed: None.

Alam Syed, MD

LONG BEACH RADIATION ONCOLOGY MEDICAL GROUP

Disclosure:
No relationships to disclose.

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Send Email for Alam Syed


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