RESUMO
PURPOSE: Low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy are known to be effective in the treatment of lip carcinomas. The aim of this study was to retrospectively compare oncologic and toxicity outcomes between the two techniques. PATIENTS AND METHODS: From 2007 to 2018, patients at the Institut de cancérologie de Lorraine (France) who received exclusive or adjuvant interstitial brachytherapy for lip squamous carcinomas were studied. Two groups were defined: the LDR/PDR group, including patients treated with iridium-192 wires, or pulsed-dose rate technique, and the high-dose-rate group, with patients treated by high-dose-rate technique. The dose ranged between 50Gy and 65Gy (depending on previous surgery) for low-dose-/pulsed-dose rate treatments, and 39Gy for high-dose-rate (twice a day). Early, late toxicity events and oncologic control were reported. RESULTS: Among the 61 patients whose data were analyzed retrospectively, 36 received the low-dose-/pulsed-dose rate treatment (59%) and 25 the high-dose-rate brachytherapy (41%). The median follow-up time was 44 months. At 36 months, the local control rates were 96.3% for LDR/PDR group and 100% for HDR (P=0.180). The regional control rates were 85.9% and 92% without any difference according to the two groups (P=0.179). The specific overall survival rate was 95.5% with no difference between groups. There were more grade 2 or higher mucositis in the HDR group than in LDR/PDR group (40% versus 16.7%, P=0.042). One case of grade 3 mucositis was recorded in each group. No grade 3 late complications were recorded. High-dose-rate brachytherapy reduced the length of hospitalization by 2 days (P<0.001). CONCLUSION: High-dose- or low-dose-/pulsed-dose rate brachytherapy seemed to be as effective and well tolerated in our experience of 61 patients.
RESUMO
PURPOSE: To focus on technical aspects of the implementation of interstitial high dose rate brachytherapy, with a step-by-step approach. MATERIALS AND METHODS: Patients were selected during multidisciplinary tumor boards, according to inclusion criteria adapted from GEC-ESTRO guidelines. A CT scan was performed a few days before implantation. On pre-implant CT, using surgical scar and clips, surgical and pathological reports, and preoperative images, we delineated the tumor bed to be included in the Clinical Target Volume (CTV), according to GEC ESTRO Recommendations. A 3D virtual implant simulation of the best catheter positions was performed in order to cover the target volume. Implantation was then carried out under local anaesthetic using 3D projections of the catheter inlets and outlets. Dosimetry was performed on post-implantation CT scan. A dose of 34Gy was delivered in 10 fractions. Acute and late side effects, and local control were evaluated 2 and 8 months after treatment. RESULTS: Between July 2017 and January 2020, 20 patients were treated with accelerated partial breast irradiation. Dose constraints regarding target volume coverage, overdose, dose homogeneity, conformation index and organs at risk were met in 94.7%, 100%, 63.2%, 0% and 89.5% of the treatment plans, respectively. Grade 1-2 acute adverse events were observed in 21% of patients, with no grade 3-4 events. CONCLUSION: The first dosimetric results and early clinical tolerance and efficacy achieved by the implementation of breast interstitial multicatheter brachytherapy in routine clinical practice are very encouraging, and confirm the interest of extending this practice.
