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Introduction: Stereotactic MR-guided on-table adaptive radiotherapy (SMART) allows the precise delivery of high-dose radiation to tumors in great proximity to radiation-sensitive organs. The aim of this study is to evaluate the toxicity and clinical outcome in locally advanced or recurrent pancreatic tumors, with or without prior irradiation, treated with SMART. Methods: Patients were treated for pancreatic cancer (PC) using SMART technology to a prescribed dose of 50 Gy (BED10, 100 Gy) in five fractions, with daily on-table adaptation of treatment plan. Endpoints were acute and late toxicities, local control, local disease-free period, and overall survival. Results: A total of 54 PC patients were treated between August 2019 and September 2022, with a median follow-up of 8.9 months from SMART. The median age was 70.4 (45.2-86.9) years. A total of 40 patients had upfront inoperable PC (55% were locally advanced and 45% metastatic), and 14 had local recurrence following prior pancreatectomy (six patients also had prior adjuvant RT). Of the patients, 87% received at least one chemotherapy regimen (Oxaliplatin based, 72.2%), and 25.9% received ≥2 regimens. Except from lower CA 19-9 serum level at the time of diagnosis and 6 weeks prior to SMART in previously operated patients, there were no significant differences in baseline parameters between prior pancreatectomy and the inoperable group. On-table adaptive replanning was performed for 100% of the fractions. No patient reported grade ≥2 acute GI toxicity. All previously irradiated patients reported only low-grade toxicities during RT. A total of 48 patients (88.9%) were available for evaluation. Complete local control was achieved in 21.7% (10 patients) for a median of 9 months (2.8-28.8); three had later local progression. Eight patients had regional or marginal recurrence. Six- and 12-month OS were 75.0% and 52.1%, respectively. Apart from mild diarrhea 1-3 months after SMART and general fatigue, there were no significant differences in toxicity and outcomes between post-pancreatectomy and inoperable groups. Conclusion: SMART allows safe delivery of an ablative dose of radiotherapy, with minimal treatment-related toxicity, even in previously resected or irradiated patients. In this real-world cohort, local control with complete response was achieved by 20% of the patients. Further studies are needed to evaluate long-term outcome and late toxicity.
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Background: We present our experience with MR-guided stereotactic body radiotherapy (SBRT) for 200 consecutive patients with prostate cancer with minimum 3-month follow-up. Methods: Treatment planning included fusion of the 0.35-Tesla planning MRI with multiparametric MRI and PET-PSMA for Group Grade (GG) 2 or higher and contour review with an expert MRI radiologist. No fiducials or rectal spacers were used. Prescription dose was 36.25 Gy in 5 fractions over 2 weeks to the entire prostate with 3-mm margins. Daily plan was adapted if tumor and organs at risk (OAR) doses differed significantly from the original plan. The prostate was monitored during treatment that was automatically interrupted if the target moved out of the PTV range. Results: Mean age was 72 years. Clinical stage was T1c, 85.5%; T2, 13%; and T3, 1.5%. In addition, 20% were GG1, 50% were GG2, 14.5% were GG3, 13% were GG4, and one patient was GG5. PSA ranged from 1 to 77 (median, 6.2). Median prostate volume was 57cc, and 888/1000 (88%) fractions required plan adaptation. The most common acute GU toxicity was Grade I, 31%; dysuria and acute gastrointestinal toxicity were rare. Three patients required temporary catheterization. Prostate size of over 100cc was associated with acute fatigue, urinary hesitance, and catheter insertion. Prostate Specific Antigen (PSA) decreased in 99% of patients, and one patient had regional recurrence. Conclusion: MR-guided prostate SBRT shows low acute toxicity and excellent short-term outcomes. Real-time MRI ensures accurate positioning and SBRT delivery.
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BACKGROUND: Anal squamous cell carcinoma (ASqCC) is a rare malignancy, traditionally treated with combined chemoradiation, with a continuous infusion of 5-fluorouracil (5-FU) and mitomycin C (MMC). Replacing intravenous (IV) 5-FU with oral capecitabine (oral fluoropyrimidine) has been reported as a non-inferior treatment option. However, these data are scarce, with variable results. OBJECTIVES: To examine the outcome of patients with ASqCC treated with either IV 5-FU or capecitabine concomitantly with radiation therapy. To compare treatment side effects, local recurrence, and general outcome. METHODS: We reviewed charts of patients who were diagnosed with stage I-III ASqCC. All participating patients received chemoradiation at the Assuta Medical Center between 2011 and 2019. RESULTS: In this study, 43 patients with ASqCC were eligible; 14 received 5-FU and 29 were treated with capecitabine. Basic characteristics were similar between the two groups, with longer follow-up for the 5-FU group. Six months following treatment, 100% (13/13 with adequate follow-up) of the 5-FU group had complete clinical response, compared to 84% in the capecitabine group (21/24), P = 0.143. The local recurrence incidence was higher in the 5-FU group at 23% (7, 10, 26 months following therapy, and none in the capecitabine group (P = 0.088). Although local and hematological toxicities were similar between groups, one patient receiving capecitabine died during chemoradiotherapy. CONCLUSIONS: Oral capecitabine demonstrated non-inferior disease control in ASqCC treated with chemoradiotherapy. We recommend oral capecitabine over continuous IV 5-FU in locally and locally advanced ASqCC. Close monitoring of side effects is required to reduce major toxicity.
