A Phase II Trial of Stereotactic Body Radiation Therapy and Androgen Deprivation for Oligometastases in Prostate Cancer (SBRT-SG 05).

PURPOSE: SBRT-Spanish Group-05 (ClinicalTrials.gov.Identifier: NCT02192788) is a collaborative (SBRT-SG, Grupo de Investigación Clínica en Oncología Radioterápica, and Sociedad Española de Oncología Radioterápica) prospective multicenter phase II trial testing stereotactic body radiation therapy (SBRT) and androgen deprivation therapy (ADT) in patients with oligorecurrent prostate cancer. METHODS AND MATERIALS: Two cohorts of patients with prostate cancer in an oligorecurrent stage (hormone-sensitive in the principal cohort and castration-resistant in the exploratory cohort) were assigned to receive ADT and SBRT for at least 24 months from the time of the enrollment. Concomitant treatment with chemotherapy, abiraterone, or enzalutamide was not allowed. Oncologic outcomes were assessed in both cohorts. Toxicity was prospectively analyzed. RESULTS: From 2014 to 2019, 81 patients with a total of 126 lesions from 14 centers met the inclusion criteria, 14 of whom were castration-resistant. With a median follow-up of 40 months (12-58 months), 3-year local recurrence-free survival was 92.5% (95% CI, 79.9%-96.3%) and 85.7% (95% CI, 48.2%-95.6%) in the principal and exploratory cohorts, respectively. In the principal cohort, biochemical relapse-free survival and metastasis progression-free survival at 1, 2, and 3 years were 91% (95% CI, 81%-95.8%), 73.7% (95% CI, 61.1%-82.8%), 50.6% (95% CI, 36.2%-63.3%), and 92% (95% CI, 83%-97%), 81% (95% CI, 70%-89%), and 67% (95% CI, 53%-77%), respectively. In the exploratory cohort, metastasis progression-free survival at 1, 2, and 3 years was 64% (95% CI, 34%-83%), 43% (95% CI, 18%-66%), and 26% (95% CI, 7%-51%), respectively. None of the patients developed grade III or higher toxicity or symptoms related to local progression, and only 2 (2.4%) patients developed grade II toxicity. CONCLUSIONS: The combination of SBRT and ADT is safe and shows favorable clinical outcomes in patients with hormone-sensitive and castration-resistant prostate cancer. Validation studies are needed in patients with castration-resistant prostate cancer.

Prospective study on stereotactic body radiotherapy for small pancreatic neuroendocrine tumors: tolerance and effectiveness analysis.

INTRODUCTION: Surgery is the standard treatment for pancreatic neuroendocrine tumors (pNETs), obtaining favorable results but associating high morbidity and mortality rates. This study assesses stereotactic body radiation therapy (SBRT) as a radical approach for small (< 2 cm) nonfunctioning pNETs. MATERIALS AND METHODS: From January 2017 to June 2023, 20 patients with small pNETs underwent SBRT in an IRB-approved study. Endpoints included local control, tolerance, progression-free survival, and overall survival (OS). Diagnostic assessments comprised endoscopy, CT scans, OctreScan or PET-Dotatoc, abdominal MRI, and histological confirmatory samples. RESULTS: In a 30-month follow-up of 20 patients (median age 55.5 years), SBRT was well-tolerated with no grade > 2 toxicity. 40% showed morphological response, 55% remained stable. Metabolically, 50% achieved significant improvement. With a median OS of 41.5 months, all patients were alive without local or distant progression or need for surgical resection. CONCLUSION: SBRT is a feasible and well-tolerated approach for small neuroendocrine pancreatic tumors, demonstrating effective local control. Further investigations are vital for validation and extension of these findings.

Salvage brachytherapy for locally-recurrent prostate cancer after radiation therapy: A comparison of efficacy and toxicity outcomes with high-dose rate and low-dose rate brachytherapy.

BACKGROUND: Brachytherapy (BT) is widely used for salvage therapy in patients with biochemical failure (BF) after radiotherapy for prostate cancer (PCa). Although low-dose-rate (LDR) and high-dose-rate (HDR) BT are both used for salvage therapy, it is not clear whether there are any differences between these two approaches in terms of efficacy or toxicity in this setting. Therefore, we review the institutional experience of the members of the Urological Tumour Working Group (URONCOR) of the Spanish Society of Radiation Oncology (SEOR) to compare these two techniques. METHODS AND MATERIALS: Between 2001 and 2016, 119 patients with biopsy-proven, locally-recurrent PCa underwent salvage BT (LDR, n = 44; HDR, n = 75) after primary radiotherapy. Relapse-free survival (RFS) and cause-specific survival (CSS) after salvage therapy were analyzed. Toxicity was assessed according to the RTOG scale. RESULTS: Median follow-up after salvage BT was 52 months. Overall, the 5-year prostate-specific antigen (PSA) RFS rate was 71% (95% CI, 65.9%-75.9%). No significant between-group differences in RFS were observed (p = 0.063). Five-year CSS for the LDR- and HDR-BT groups were 96.5% and 93%, respectively. Overall, 38 patients (32%) developed biochemical progression (Phoenix definition) after salvage BT: 14 patients (32%) in the LDR group and 24 (32.5%) in the HDR group. On the multivariate analysis, the following variables were significantly associated with progression, time to BF from primary radiotherapy <30 months (p = 0.014); and post-salvage nadir PSA (p = 0.000). There were no significant between-group differences in toxicity. Overall, there were 13 cases of urethral stricture, 22 cases of urinary incontinence, and 13 cases of haematuria. Toxicity ≥grade 3 was observed in 23.5% of patients. CONCLUSIONS: These findings show that both HDR-BT and LDR-BT yield comparable efficacy and toxicity outcomes in patients undergoing salvage treatment for locally-recurrent prostate cancer after primary radiotherapy. Predictors of worse outcomes after salvage BT were post-salvage nadir PSA and time to BF from initial radiotherapy.