Spatial rectal dose/volume metrics predict patient-reported gastro-intestinal symptoms after radiotherapy for prostate cancer.
Ontology highlight
ABSTRACT: BACKGROUND:Gastro-intestinal (GI) toxicity after radiotherapy (RT) for prostate cancer reduces patient's quality of life. In this study, we explored associations between spatial rectal dose/volume metrics and patient-reported GI symptoms after RT for localized prostate cancer, and compared these with those of dose-surface/volume histogram (DSH/DVH) metrics. MATERIAL AND METHODS:Dose distributions and six GI symptoms (defecation urgency/emptying difficulties/fecal leakage, ?Grade 2, median follow-up: 3.6?y) were extracted for 200 patients treated with image-guided RT in 2005-2007. Three hundred and nine metrics assessed from 2D rectal dose maps or DSHs/DVHs were subject to 50-times iterated five-fold cross-validated univariate and multivariate logistic regression analysis (UVA, MVA). Performance of the most frequently selected MVA models was evaluated by the area under the receiving-operating characteristics curve (AUC). RESULTS:The AUC increased for dose-map compared to DSH/DVH-based models (mean SD: 0.64?±?0.03 vs. 0.61?±?0.01), and significant relations were found for six versus four symptoms. Defecation urgency and faecal leakage were explained by high doses at the central/upper and central areas, respectively; while emptying difficulties were explained by longitudinal extensions of intermediate doses. CONCLUSIONS:Predictability of patient-reported GI toxicity increased using spatial metrics compared to DSH/DVH metrics. Novel associations were particularly identified for emptying difficulties using both approaches in which intermediate doses were emphasized.
SUBMITTER: Casares-Magaz O
PROVIDER: S-EPMC6619498 | biostudies-literature | 2017 Nov
REPOSITORIES: biostudies-literature
ACCESS DATA