In 2016, international consensus clinical target volume (CTV) guidelines for adjuvant radiation treatment (ART) after radical cystectomy (RC) in muscle-invasive bladder cancer patients with high risk for locoregional failure (LRF) were published.
A subsequent external validation study recommended several CTV optimizations (CTV-OPT). This study aimed to update international consensus guidelines based on new clinical experiences.
Phase 1 (delineation interobserver variability): 4 observers delineated the CTV of 9 patients post-RC, as in clinical practice. Interobserver agreement in contouring was evaluated using volume- and kappa-statistics. Phase 2 (pattern of failure analysis): Among a prospective cohort of 72 patients treated with ART, 11 developed LRF (10 available for review). LRFs were mapped in predefined pelvic subsites (i.e. common, external and internal iliac, obturator and presacral node regions and cystectomy bed) and their distance to CTV-OPT was measured. The actual delivered dose at each relapse site was calculated. Phase 3 (review CTV): Based on the results of phase 1 and 2, 5 senior radiation-oncologists (XXXX) reviewed the published CTV borders and provided an update when indicated.
Phase 1: The mean overall kappa-value was 0.66 (range: 0.60-0.70), indicating substantial overall agreement per Landis-Koch criteria. Specific kappa-values per area indicated for the common iliac and obturator node regions only slight and moderate variability, respectively. Phase 2: 13 out of 16 LRFs centers were not included in the CTV-OPT. 10 LRF sites received a median dose <45Gy, of which 6 were located in the cystectomy bed that was not included in the CTV because of negative RC margins. Phase 3: Key recommendations by the panel were to include the entire common iliac node region and the cystectomy bed regardless of surgical margin status and re-affirmed to not crop the CTV out of bowel.
International consensus guidelines were updated.
Practical radiation oncology. 2022 Jun 09 [Epub ahead of print]
Flor Verghote, Paul Sargos, John P Christodouleas, Vedang Murthy, Brian C Baumann, Piet Dirix, Charlien Berghen, Leen Paelinck, Tom Vercauteren, Valérie Fonteyne
Department of Radiotherapy-Oncology, Ghent University Hospital, Ghent, Belgium.; Department of Human Structure and Repair, Ghent University, Ghent, Belgium.. Electronic address: ., Department of Radiotherapy, Institut Bergonié, Bordeaux, France., Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Department of Radiation Oncology, ACTREC, Tata Memorial Centre, HBNI, Mumbai, India., Department of Radiation Oncology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri., Department of Radiation-Oncology, Iridium Network, Antwerp, Belgium., Department of Radiation-Oncology, University Hospitals Leuven, Leuven, Belgium., Department of Radiotherapy-Oncology, Ghent University Hospital, Ghent, Belgium., Department of Radiotherapy-Oncology, Ghent University Hospital, Ghent, Belgium.; Department of Human Structure and Repair, Ghent University, Ghent, Belgium.
PubMed http://www.ncbi.nlm.nih.gov/pubmed/35691550