Objectives: Modern radiotherapy (RT) techniques require careful delineation of the target. There is no particular RT contouring guideline for patients receiving NACT (neoadjuvant chemotherapy). In this study, we examined the distribution of pre-chemotherapy clinically positive nodal metastases. Methods: We explored the coverage rate of the RTOG breast contouring guideline by deformable fusion of 18-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scan. We retrospectively evaluated neoadjuvant chemotherapy patients. All PET-CT images were imported into the planning software. We combined the planning CT and the CT images of PET-CT with rigid and then a deformable registration. We manually contoured positive lymph nodes on the CT component of the PET-CT data set and transferred them to planning CT after fusion. We evaluated whether previously contoured lymphatic CTVs, according to the RTOG breast atlas, include GTV-LNs. Results: All breast cancer patients between October 2018- February 2021 were evaluated from the electronic database. There were 142 radiologically defined positive lymph nodes in 31 patients who were irradiated after NACT. Most LNs (70%) were in the level I axilla. Only 71.1% (n:101) of the whole lymph nodes in 10 patients were totally covered, 22.5% (n:32) partially covered and 6.4% %(n:9) totally under covered. Conclusions: The extent of regional nodal areas in the RTOG atlas may be insufficient to cover positive lymph nodes adequately. For patients with nodal involvement undergoing neoadjuvant chemotherapy, PET-CT image fusions can be helpful to be sure that positive lymph nodes are in the treatment volume. Advances in knowledge: RTOG contouring atlas may be insufficient to cover all involved lymph nodes after NACT. For patients with nodal involvement undergoing neoadjuvant chemotherapy, PET-CT image fusions may help to be sure that positive lymph nodes are in the treatment volume.

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Background: Intra-fractional motion is one of the main challenges in SBRT. Breath-hold (BH) technique minimizes the tumor motion. However, reproducibility and consistency are critically important. Surface tracking systems integrated into treatment enable motion tracking with three-dimensional camera technology. Surface guidance was integrated with Varian EDGE and used at multiple treatment sites since 2018 in our department. After four years of experience, in this study, we aim to publish patient-reported outcomes (PROMs), feasibility, and tolerability of surface guidance (SGRT) with breath-hold SBRT in a specific subgroup: liver metastases. Methods: Patients with liver metastasis treated with breath-hold and SGRT were evaluated prospectively. Two-step, seven-question surveys were applied after CT simulation and treatment. Treatment duration and BH number were recorded. In addition, factors that can affect the SGRT and treatment time were evaluated. Results: Between April 2021- May 2022, 41 patients were treated in 171 fractions. According to the PROMs, previous training was beneficial, and holding breath is tolerable. Patients have a little stress about taking an active role in the treatment. Karnosky performance status (KPS), age, lung volume, or any condition affecting lung capacity, previous BH history, and being a native speaker are not correlated with treatment time and BH with SGRT tolerability. Only female patients have better BH performance with SGRT treatments than male patients (p: 0,02). Conclusion: SGRT applications in BH are tolerable and feasible in liver SBRT treatments. There is no specific subgroup that cannot be tolerated with this method.

Introduction: Stereotactic radiosurgery (SRS) has become a preferred treatment in the initial management of brain metastases (BM). This study reported treatment outcomes and identified the patient, tumour, and treatment-related factors that predict failure, survival, and brain necrosis (BN). Methods: We retrospectively reviewed the electronic medical records of all BM patients treated with SRS. Patient, tumour characteristics and treatment details data were collected. All recurrences and BN were defined in the neurooncological tumour board. Results: From December 2016 to April 2020, 148 patients were analysed. The median follow-up was 14·8 months (range 6–51). At the time of analyses, 72·3% of the patients were alive. Presence of initial neurological deficit (HR; 2·71 (1·07–6·9); p = 0·036) and prior RT (HR; 2·55 (1·28–5·09); p = 0·008) is associated with worse overall survival. The local recurrence rate was 11·5 %. The distant brain metastasis rate was 53·4 %. Leptomeningeal metastasis was seen in 11 patients (7·4%). Symptomatic BN was seen in 19 patients (12·8 %). Bigger lesions (13 versus 23 mm diameter; p = 0·034) and cavity radiosurgery are associated with more BN (63·2 % versus 36·8%; p: 0·004). Conclusions: Distant BM is the leading cause of CNS recurrences and, salvage SRS is possible. Due to the increasing risk of developing BN routine metastasectomy should be made with caution.

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