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Introduction: Since radical treatments in low risk prostate cancer do not improve overall survival in comparison to active surveillance, preserving quality of life (QOL) remains the key objective. Active surveillance of indolent prostate cancer avoids curative treatment side-effects but necessitates repeated biopsies. Focal stereotactic body radiation therapy (focal SBRT) may be an alternative. This non-randomized Phase-II trial examined the feasibility and safety of focal SBRT for low and favorable intermediate-risk prostate cancer. Methods: Patients were recruited in 2016-2019 if they had: localized CAPRA ≤ 3 prostate adenocarcinoma; an isolated PIRADS≥4 macroscopic tumor on MRI; WHO Performance Status 0-1; and no major urinary symptoms. 36.25 Gy (80% isodose prescription) were delivered in 5 fractions every other day. Primary outcome was delay between focal SBRT and salvage-treatment initiation. Secondary outcomes were: acute/late genitourinary/rectal toxicity; biological, clinical and MRI local control; and change in QOL measures. Results: Over a median follow-up of 36 months, salvage prostatectomy in the 24 eligible patients was never required. Three-year biochemical progression-free survival was 96%. The single biochemical recurrence was a small (2-mm) Gleason 6 (3 + 3) lesion in the non-irradiated lobe. All 19 patients with ≥1 post-treatment MRI evaluations demonstrated complete radiological response. Acute/late grade ≥3 toxicities did not occur: all acute toxicities were grade-1 genitourinary (38% patients), grade-2 genitourinary (8%), or grade-1 rectal (13%) toxicities. There was one (4%) late grade-1 genitourinary toxicity. QOL was unchanged at last follow-up, as shown by IPSS (2.86 to 3.29, p>0.05), U-QOL (0.71 to 0.67, p>0.05), and IIEF5 (the 14 initially potent patients maintained potency (IIEF5 > 16)). Conclusion: Focal SBRT is feasible, well-tolerated, and preserves QOL. This innovative robotized approach challenges active surveillance.
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BACKGROUND: Segmentation is a crucial step in treatment planning that directly impacts dose distribution and optimization. The aim of this study was to evaluate the inter-individual variability of common cranial organs at risk (OAR) delineation in neurooncology practice. METHODS: Anonymized simulation contrast-enhanced CT and MR scans of one patient with a solitary brain metastasis was used for delineation and analysis. Expert professionals from 16 radiotherapy centers involved in brain structures delineation were asked to segment 9 OAR on their own treatment planning system. As reference, two experts in neurooncology, produced a unique consensual contour set according to guidelines. Overlap ratio, Kappa index (KI), volumetric ratio, Commonly Contoured Volume, Supplementary Contoured Volume were evaluated using Artiview™ v 2.8.2-according to occupation, seniority and level of expertise of all participants. RESULTS: For the most frequently delineated and largest OAR, the mean KI are often good (0.8 for the parotid and the brainstem); however, for the smaller OAR, KI degrade (0.3 for the optic chiasm, 0.5% for the cochlea), with a significant discrimination (p < 0.01). The radiation oncologists, members of Association des Neuro-Oncologue d'Expression Française society performed better in all indicators compared to non-members (p < 0.01). Our exercise was effective in separating the different participating centers with 3 of the reported indicators (p < 0.01). CONCLUSION: Our study illustrates the heterogeneity in normal structures contouring between professionals. We emphasize the need for cerebral OAR delineation harmonization-that is a major determinant of therapeutic ratio and clinical trials evaluation.