OBJECTIVE: A Benchmark Case (BC) was performed as part of the quality assurance process of the randomized phase 2 GORTEC 2014-14 OMET study, testing the possibility of multisite stereotactic radiation therapy (SBRT) alone in oligometastatic head and neck squamous cell carcinoma (HNSCC) as an alternative to systemic treatment and SBRT.
METHODS: Compliance of the investigating centers with the prescription, delineation, planning and evaluation recommendations available in the research protocol was assessed. In addition, classical dosimetric analysis was supplemented by quantitative geometric analysis using conformation indices.
RESULTS: Twenty centers participated in the BC analysis. Among them, four major deviations (MaD) were reported in two centers. Two (10%) centers in MaD had omitted the satellite tumor nodule and secondarily validated after revision. Their respective DICE indexes were 0.37 and 0 and use of extracranial SBRT devices suboptimal There were significant residual heterogeneities between participating centers, including those with a similar SBRT equipment, with impact of plan quality using standard indicators and geometric indices.
CONCLUSIONS: A priori QA using a BC conditioning the participation of the clinical investigation centers showed deviations from good SBRT practice and led to the exclusion of one out of the twenty participating centers. The majority of centers have demonstrated rigorous compliance with the research protocol. The use of quality indexes adds a complementary approach to improve assessment of plan quality.

Metastatic involvement of the pancreas occurs in 5% of patients affected by advanced malignancies. Surgical resection has been reported by number of authors as a valuable option to improve disease control, in particular in patients with limited disease burden and favourable histotypes; however, the benefit of this procedure has been questioned due to patient selection, technical challenges and relevant risk of perioperative mortality and severe complications. In the present study, a cohort of surgically unfit patients affected by a solitary metastasis in the pancreas from various primary tumours received stereotactic radiotherapy with an ablative dose schedule, obtaining promising local and distant disease progression-free delay with minor toxicity. This is the first report to our knowledge on the use of ablative stereotactic radiotherapy of metastasis in the pancreatic gland.