RESUMO
BACKGROUND: To investigate progression free survival (PFS), local control (LC) and overall survival (OS) outcomes for patients treated with spine hypofractionated stereotactic ablative radiotherapy (SABR) and to evaluate possible predictors of rapid progression in view of a correct patient selection for this potentially curative SABR. MATERIALS AND METHODS: A cohort of 59 patients with spinal metastases were treated with SABR. Patient selection criteria were the following: histologically proven diagnosis of a solid tumor, a World Health Organization (WHO) score ≤ 2, life expectancy > 6 months, Spinal Instability Neoplastic Score (SINS) ≤ 12 points and presenting with radically treated oligometastatic disease (≤5 lesions) or stable polymetastatic disease with an oligoprogressive lesion. RESULTS: From March 2015 to June 2019, 59 patients were treated with Linac-based SABR to 64 spinal metastases with a median follow-up of 55 months. SABR was standard delivered every other day in 3 to 10 fractions with median prescription dose of 27 Gy (range 21-49 Gy).The 1-,2- and 5-year PFS was 98%, 85% and 75% for all patients. OS at 5 years for all patients was 92%. Metachronous lesions (p < 0.01; HR = 7.1) and oligometastatic (vs. oligoprogressive) lesions (p = 0.02; HR = 0.3) were associated with higher PFS in uni- and multivariate Cox regression analysis. No significant predictors in multivariate analysis were demonstrated for rapid progressors.Vertebral compression fractures developed de novo in 6.3% (4/64) of cases. The median time to fracture was 11 months (range 7-15) after treatment. No other adverse events ≥ 3 grade were observed. CONCLUSIONS: Tumor control and toxicity after high-dose hypofractionated SABR was evaluated in patients with spinal oligometastases. High rates of efficacy and minimal toxicity were demonstrated. Oligometastatic patients with metachronous spinal metastases seem to benefit the most from SABR.
RESUMO
BACKGROUND AND PURPOSE: The TRENDY trial is an international multi-center phase-II study, randomizing hepatocellular carcinoma (HCC) patients between transarterial chemoembolization (TACE) and stereotactic body radiation therapy (SBRT) with a target dose of 48-54â¯Gy in six fractions. The radiotherapy quality assurance (QA) program, including prospective plan feedback based on automated treatment planning, is described and results are reported. MATERIALS AND METHODS: Scans of a single patient were used as a benchmark case. Contours submitted by nine participating centers were compared with reference contours. The subsequent planning round was based on a single set of contours. A total of 20 plans from participating centers, including 12 from the benchmark case, 5 from a clinical pilot and 3 from the first study patients, were compared to automatically generated VMAT plans. RESULTS: For the submitted liver contours, Dice Similarity Coefficients (DSC) with the reference delineation ranged from 0.925 to 0.954. For the GTV, the DSC varied between 0.721 and 0.876. For the 12 plans on the benchmark case, healthy liver normal-tissue complication probabilities (NTCPs) ranged from 0.2% to 22.2% with little correlation between NCTP and PTV-D95% (R2â¯<â¯0.3). Four protocol deviations were detected in the set of 20 treatment plans. Comparison with co-planar autoVMAT QA plans revealed these were due to too high target dose and suboptimal planning. Overall, autoVMAT resulted in an average liver NTCP reduction of 2.2 percent point (range: 16.2 percent point to -1.8 percent point, pâ¯=â¯0.03), and lower doses to the healthy liver (pâ¯<â¯0.01) and gastrointestinal organs at risk (pâ¯<â¯0.001). CONCLUSIONS: Delineation variation resulted in feedback to participating centers. Automated treatment planning can play an important role in clinical trials for prospective plan QA as suboptimal plans were detected.
