SRS for the treatment of limited brain metastases (BM) is widely accepted, but there are still limitations in the management of numerous BM. Frameless single-isocenter multitarget SRS is a novel technique that allows for rapid treatment delivery to multiple BM. We report our preliminary clinical, dosimetric, and patient´s shifts outcomes with this technique. We have reviewed clinical and dosimetric outcomes of patients with intact BM treated with SRS using one isocenter either for single (1BM) or multiple (≥ 2BM) targets). Immobilization was based on an SRS stereotactic mask. Elements Multiple Brain Mets SRS (Brainlab AG, Munich, Germany) software was used for registration, image fusion, target contouring, and treatment planning. Exactrac Dynamic (Brainlab AG, Munich, Germany) and a 6 degree of freedom couch were used for monitoring, correcting the position and assessing and applying residual errors also when couch rotations. During dose delivery, the patient position was monitored and registered using surface tracking and stereoscopic X-rays. From May 2022 to December 2023, we treated 60 patients with a total of 255 BM. The 67

PURPOSE:This study evaluated the feasibility and tolerability of SABR in patients with high- and very-high-risk prostate cancer. METHODS AND MATERIALS:A prospective study included patients with high-risk and N1 prostate cancer. SABR was delivered as 40 Gy in 8 Gy fractions, with optional elective nodal irradiation (26 Gy in 5.2 Gy fractions) and a 40 Gy nodal boost for N1 disease. The treatment protocol involved 24 to 36 months of androgen deprivation therapy, premedication with alpha-1 receptor antagonists, and dexamethasone (4 mg on treatment days). Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events v5.0, while quality of life was assessed using the EORTC QLQ-C30 and QLQ-PR25 questionnaires at the final check-up. RESULTS:The study included 96 patients (median age 77.2 years) with a median follow-up of 29.8 months. Elective nodal radiation therapy was delivered to 66.7% of patients, and 16.8% received a nodal boost. Acute grade 2 (G2) genitourinary and gastrointestinal (GI) events occurred in 5.2% and 7.3% of patients, respectively, with no grade ≥3 acute events. Late grade ≥2 genitourinary and GI events were observed in 7.8% and 15.7% of patients, respectively, including 1 grade 4 GI event. Common late symptoms included nocturia and rectal bleeding. Most patients (86.5%) reported no or minor difficulties posttreatment, though challenges with sexual activity, nocturia, and incontinence were noted. Physicians underestimated urgency and nocturia and overestimated rectal bleeding. CONCLUSIONS:SABR delivering 40 Gy in 5 fractions is feasible and well-tolerated for high-risk prostate cancer, with minimal additional toxicity from elective nodal irradiation and a boost to N1 disease. These findings support SABR as an effective treatment, warranting further long-term studies.

Background:Recurrent high-grade gliomas present a therapeutic challenge. Repeat surgery, re-irradiation, and systemic therapy have been explored, with re-irradiation requiring precise tumor relapse delineation and advanced dosimetric techniques. This study aims to evaluate the effectiveness and tolerability of re-irradiation using Hypofractionated Stereotactic Radiation (HFSRT) schedules. Materials and methods:In a retrospective analysis from 2011 to 2021, 52 adult patients with recurrent high-grade gliomas were examined, including 42.3% with glioblastoma, 32.5% with grade 3 gliomas, and 25% with grade 2 gliomas as initial diagnosis. All received prior radiotherapy at doses ranging from 54-60 Gy, with a median time to tumor relapse of 19.8 months. Salvage surgery was performed in 42.3% of cases, with a median interval of 22.45 months between radiation courses. Re-irradiation doses were 30 Gy in 5 fractions for 54% and 40 Gy in 10 fractions for 46%. Concurrent systemic treatments included temozolomide (30.8%), nevacizumab (27%), or none (35%). Results:In-field and out-field tumor progression occurred in 65.4% and 25% of patients, with median times to local and distant progression of 5.17 and 4.57 months. Median overall survival (OS) from re-irradiation was 12 months. Univariate analysis showed a trend favoring 30 Gy in 5 fractions for disease progression-free survival (DPFS). Treatment was generally well-tolerated, with only 5.7% experiencing acute Grade-3 toxicity, and symptomatic radionecrosis occurred in 2 patients. Conclusion:Re-irradiation using HFSRT for recurrent high-grade gliomas is viable and well-tolerated, demonstrating survival rates comparable to existing literature. These findings underscore the potential of HFSRT in managing recurrent high-grade gliomas.

This study aimed to assess the efficacy and tolerability of stereotactic body radiation therapy (SBRT) for the treatment of liver metastases. Patients with up to 5 liver metastases were enrolled in this prospective multicenter study and underwent SBRT. Efficacy outcomes included in-field local control (LC), progression-free survival (PFS), and overall survival (OS). Acute and late toxicities were evaluated using CTCAE v.4.0. A total of 52 patients with 105 liver metastases were treated between 2015 and 2018. The most common primary tumor was colorectal cancer (72

PURPOSE:This study aims to investigate lattice radiotherapy (LRT) for bulky tumor in 10 patients, analyzing geometrical and dosimetrical parameters and correlations among variables. METHODS:Patients were prescribed a single-fraction of 18 Gy to 50 % of each spherical vertex (1.5 cm diameter). Vertices were arranged in equidistant planes forming a triangular pattern. Center-to-center distance (Dc-c) between vertices was varied from 4 to 5 cm. A new method for calculating the valley-to-peak dose ratio (VPDR) was proposed and compared to other two from existing literature. GTV volumes (VGTV), vertex number (Nvert), low-dose related parameters and vertex D99%, D50%, and D1% were recorded. Beam-on time and Monitor Units (MU) were also evaluated. Correlations were assessed using Spearman's coefficient, with significant differences analyzed using Mann-Whitney U test. RESULTS:Tumor volumes ranged from 417 to 3615 cm3. Median vertex number was 14.5 (IQR:11.3-17.8). VPDR ranged from 0.16 to 0.28. Median D99% spanned from 10.0 to 13.7 Gy, median D50% exceeded 18.0 Gy, and median D1% surpassed 23.3 Gy. Periphery dose remained under 4.0 Gy. Plans exhibited high modulation, with median beam-on time and MU of 8.8 min (IQR:8.2-10.1) and 13,069 MU (IQR:11574-13639). Significant correlations were found between Nvert and VGTV (p < 0.01), MU (p < 0.02) and beam-on time (p < 0.01) and between Dc-c and two VPDR definitions (p < 0.02) and periphery dose (p < 0.01). Significant differences were observed among the three valley dose definitions (p < 0.01) and the three peak dose definitions (p < 0.01). CONCLUSIONS:Reporting geometrical and dosimetrical parameters in LRT is crucial, alongside the need for unified definitions of valley and peak doses.

Purpose: Moderate hypofractionated radiotherapy is the standard of care for all patients with breast cancer, irrespective of stage or prior treatments. While extreme hypofractionation is accepted for early-stage tumours, its application in irradiating locoregional lymph nodes remains controversial. Materials and methods: A prospective registry analysis from July 2020 to September 2023 included 276 patients with early-stage breast cancer treated with one-week ultra-hypofractionation (UHF) at 26 Gy in 5 fractions on the whole breast (58.3 %) or thoracic wall (41.7 %) and ipsilateral regional lymph nodes and simultaneous integrated boost (58.3 %). Primary endpoint was assessment of acute adverse events (AEs). Secondarily, onset of early-delayed toxicity was assessed. A minimum 6-month follow-up was required for assessing potential treatment-related early-delayed complications. Acute or late complications attributable to treatment were assessed at inclusion using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 criteria. Results: With a median follow-up of 19 months (range 1-49 months), 159 (57.6 %) patients reported AEs, predominantly grade (G) 1 (n = 139, 50.4 %) and G2 (n = 20, 7.8 %). Skin acute toxicity was common (G1/2: 134, G3: 14), while breast oedema occurred in 10 patients (G1: 9, G2: 1), and 15.9 % reported breast pain (G1: 42, G2: 2). Ipsilateral arm oedema was observed in 1.8 % patients. For patients with a follow-up beyond 6 months (n = 213), 23.4 % patients reported G1/G2 skin AEs, 8.8 % had G1/G2 breast/chest wall oedema, and 8.9 % experienced arm lymphedema. There were no cases of brachial plexopathy or G3 toxicity in this group of patients. Conclusions: One-week UHF adjuvant locoregional radiation is well-tolerated, displaying low-toxicity profiles comparable to other studies using similar irradiation schedules.

To assess the clinical outcomes of patients with spine metastases treated with SBRT at our institution. Patients with spine metastases treated with SBRT (1 fraction/18 Gy or 5 fractions/7 Gy) during the last 12 years have been analyzed. All patients were simulated supine in a vacuum cushion or with a shoulder mask. CT scans and MRI image registration were performed. Contouring was based on International Spine-Radiosurgery-Consortium-Consensus-Guidelines. Highly conformal-techniques (IMRT/VMAT) were used for treatment planning. Intra and interfraction (CBCT or X-Ray-ExacTrac) verification were mandatory. From February 2010 to January 2022, 129 patients with spinal metastases were treated with SBRT [1 fraction/18 Gy (75

Background and purpose: In lung Stereotactic Body Radiotherapy (SBRT) respiratory management is used to reduce target motion due to respiration. This study aimed (1) to estimate intrafraction shifts through a Cone Beam Computed Tomography (CBCT) acquired during the first treatment arc when deep inspiration breath-hold (DIBH) was performed using spirometry-based (SB) or surface-guidance (SG) systems and (2) to analyze the obtained results depending on lesion localization. Material and methods: A sample of 157 patients with 243 lesions was analyzed. A total of 860 and 410 fractions were treated using SB and SG. Averaged intrafraction shifts were estimated by the offsets obtained when registering a CBCT acquired during the first treatment arc with the planning CT. Offsets were recorded in superior-inferior (SI), left-right (LR) and anterior-posterior (AP). Significance tests were applied to account for differences in average offsets and variances between DIBH systems. Systematic and random errors were computed. Results: Average offset moduli were 2.4 +/- 2.2 mm and 3.5 +/- 2.6 mm for SB and SG treatments (p < 0.001). When comparing SB and SG offset distributions in each direction no differences were found in average values (p > 0.3). However, variances were statistically smaller for SB than for SG (p < 0.001). The number of vector moduli offsets greater than 5 mm was 2.1 times higher for SG. Compared to other locations, lower lobe lesions moduli were at least 2.3 times higher. Conclusions: Both systems were accuracy-equivalent but not precision-equivalent systems. Furthermore, the SB system was more precise than the SG one. Despite DIBH, patients with lower lobe lesions had larger offsets than superior lobe ones, mainly in SI.

Conservative surgery in combination with local radiation therapy is considered a standard approach for soft tissue sarcomas (STS) leading to high local control rates and widely replacing the need for amputations. A close relationship exists between total radiation dose and local control probability. Combination of external beam radiotherapy and perioperative brachytherapy represents a moderate dose escalation that could contribute to improve local control. From May 2015 to October 2018, 23 patients with histologically proven STS of various locations were prospectively entered into a data registry of perioperative HDR brachytherapy (PoBT) combined with external beam radiotherapy (EBRT). Multidisciplinary treatment comprised wide surgical excision, PoBT (16.5 Gy delivered in 3 fractions of 5.5 Gy twice daily with a gap time of at least 6 h between fractions), and EBRT delivered either pre- or postoperatively (median dose 47 Gy, range 40–57.5 Gy) up to a total accumulated radiotherapy equivalent dose for tumor of 69.5 to 86.5 Gy (median, 76.1 Gy), representing a moderate total dose escalation over the 66 Gy traditionally used. With a median follow-up of 13.4 months (range, 1–35.4 months), 22 patients (96%) remain alive without evidence of local or distant recurrence, 1 patient (4%) is alive with local relapse, and no patient has died because of tumor progression. Treatment-related adverse effects were mild or moderate. No cases of grades 4–5 late toxicity have been observed during the follow-up period. HDR PoBT is safe, feasible, and well tolerated and allows for a moderate radiation dose escalation with acceptable rates of tumor control. Further follow-up is necessary to confirm impact on final outcomes.

Introduction: Gating technique can improve the accuracy of the treatment of lung and liver lesions with SBRT, by monitoring organ tumor motion and irradiating within a selected area of the respiratory cycle. Methods: We have treated 75 patients (34 lung and 41 liver) with Novalis LINAC SBRT Adaptive Gating Technique. A total of 130 lesions, 49 lung lesions (11 primary NSCLC and 38 metastases) and 81 liver lesions (10 primary and 71 metastases). Prior to treatment, a fiducial marker is implanted and CT simulation is performed in breatholding with infrared external skin markers. Based on these external markers, internal tumor motion is correlated with the external respiratory signal. The outlined PTV includes (CTV=GTV) + 5 mm margin. The following doses are prescribed: liver (5Gy x 10 or 12-20Gy x 3), peripheral lung lesions (15-20 Gy x 3), and central lung lesions (5Gy x 10 or 10 Gy x5). The dose was delivered with multiple coplanar static beams. During patient setup, infrared markers track the respiratory cycle. Exactrac X-Rays localize the internal marker, quantify the tumor movement, and define the "beam on area" by correlating the external marker motion to the internal marker position. Intrafraction verification of the validity of this model is performed in real time by ExacTrac X-Rays. Results: 130 lesions were evaluated with 90.5% local control at two years [93.8% in lung and 87.3% in liver lesions]. Clinical tolerance was excellent and no lung or liver toxicity grade 3 was observed. Conclusion: Our clinical experience with Novalis SBRT Adaptive Gating shows that this technique is safe and efficient for the treatment of lung and liver lesions, while reducing the volume of irradiated healthy tissue. Intrafraction verification improves the treatment accuracy by a real time verification of tumor position.