Salvage HDR interventional radiotherapy for Chest wall recurrences after mastectomy and irradiation
OC-0455
Abstract
Salvage HDR interventional radiotherapy for Chest wall recurrences after mastectomy and irradiation
Authors: Tamer Soror1, Maggie Banys-Paluchowski2, Corrina Melcherta1, Kerstin Muras2, Meiting Xie2, Dirk Rades1, Joachim Rody2, György Kovács3
1University of Lübeck, Radiatiation Oncology, Lübeck, Germany; 2University of Lübeck, Obstetrics and Gynecology, Lübeck, Germany; 3Università Cattolica del Sacro Cuore, Gemelli-INTERACTS, Rome, Italy
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Purpose or Objective
Local and locoregional recurrences following mastectomy and external irradiation in locally advanced breast cancer patients remain a frequent clinical problem. The local recurrence rate (LR) rate after mastectomy and post-operative irradiation may be as low as 1.6% in node-negative disease or 8.1% in node-positive breast cancer. The purpose is to investigate the technical feasibility, safety, and efficacy of interstitial perioperative high-dose-rate interventional radiotherapy (HDR-IRT, brachytherapy as a salvage local treatment combined with surgery for local recurrences of chest wall following mastectomy and previous external beam radiation treatment (EBRT).
Material and Methods
A retrospective analysis of patients treated with interstitial HDR-IRT in combination with local surgery of a chest wall recurrence of breast cancer after previous treatment with mastectomy and EBRT from 2008 to 2020. After the surgical resection of the LR, the tumor bed was marked with metallic surgical clips. Interstitial plastic catheters were implanted and sutured to the tumor bed in a single plane with a 2 cm margin. The catheters were kept parallel to each other with an in-between distance of 8 – 12 mm. Clinical target volume (CTV) included the estimated tumor bed, the surgical clips, and a safety margin of 10 – 20 mm excluding the skin.
Figure 1. Representative samples of the dose distribution; a: transversal, b: sagittal; c: coronal; d: three-dimensional reconstruction. Green: clinical target volume; yellow: rips; orange: heart; red: reference isodose-line
Results
Fifty-four patients were identified with 57 treated lesions. The median age was 50 years (range: 34 – 79). All patients had received EBRT. The mean dose of EBRT was 52.4 Gy (± 6.4). In 71,5% of the patients, mastectomy was performed as the primary surgical treatment for breast cancer. While in 28.5% of the patients, mastectomy was a salvage treatment after local recurrence. The mean dose of the HDR-IRT was 30.2 Gy (± 3.1), delivered in 2 daily fractions.
The mean volume of the clinical target volume (CTV) as defined on CT images was 65.4cc (±9.3). The median number of the catheter was 6 (range 3 – 12). The mean CTV D90 was 98.4% (±4.1).
Local recurrence occurred in 11 patients (20.4%). The mean time for local recurrence was 12.2 months (± 6.2). Treatment-related toxicities were grade 1-2 in the form of skin toxicity or fibrosis. No grade 3 or 4 late toxicities were encountered.
Conclusion
HDR-IRT combined with surgical intervention seems to be an effective reirradiation treatment modality with acceptable toxicity for breast cancer patients suffering from chest wall local recurrences after mastectomy and previous external irradiation.