ABSTRACT
OBJECTIVES: In resectable pancreatic ductal adenocarcinoma (PDAC), few pre-operative prognostic biomarkers are available. Radiomics has demonstrated potential but lacks external validation. We aimed to develop and externally validate a pre-operative clinical-radiomic prognostic model. METHODS: Retrospective international, multi-center study in resectable PDAC. The training cohort included 352 patients (pre-operative CTs from five Canadian hospitals). Cox models incorporated (a) pre-operative clinical variables (clinical), (b) clinical plus CT-radiomics, and (c) post-operative TNM model, which served as the reference. Outcomes were overall (OS)/disease-free survival (DFS). Models were assessed in the validation cohort from Ireland (n = 215, CTs from 34 hospitals), using C-statistic, calibration, and decision curve analyses. RESULTS: The radiomic signature was predictive of OS/DFS in the validation cohort, with adjusted hazard ratios (HR) 2.87 (95% CI: 1.40-5.87, p < 0.001)/5.28 (95% CI 2.35-11.86, p < 0.001), respectively, along with age 1.02 (1.01-1.04, p = 0.01)/1.02 (1.00-1.04, p = 0.03). In the validation cohort, median OS was 22.9/37 months (p = 0.0092) and DFS 14.2/29.8 (p = 0.0023) for high-/low-risk groups and calibration was moderate (mean absolute errors 7%/13% for OS at 3/5 years). The clinical-radiomic model discrimination (C = 0.545, 95%: 0.543-0.546) was higher than the clinical model alone (C = 0.497, 95% CI 0.496-0.499, p < 0.001) or TNM (C = 0.525, 95% CI: 0.524-0.526, p < 0.001). Despite superior net benefit compared to the clinical model, the clinical-radiomic model was not clinically useful for most threshold probabilities. CONCLUSION: A multi-institutional pre-operative clinical-radiomic model for resectable PDAC prognostication demonstrated superior net benefit compared to a clinical model but limited clinical utility at external validation. This reflects inherent limitations of radiomics for PDAC prognostication, when deployed in real-world settings. KEY POINTS: ⢠At external validation, a pre-operative clinical-radiomics prognostic model for pancreatic ductal adenocarcinoma (PDAC) outperformed pre-operative clinical variables alone or pathological TNM staging. ⢠Discrimination and clinical utility of the clinical-radiomic model for treatment decisions remained low, likely due to heterogeneity of CT acquisition parameters. ⢠Despite small improvements, prognosis in PDAC using state-of-the-art radiomics methodology remains challenging, mostly owing to its low discriminative ability. Future research should focus on standardization of CT protocols and acquisition parameters.
Subject(s)
Adenocarcinoma , Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Adenocarcinoma/diagnostic imaging , Adenocarcinoma/surgery , Canada , Carcinoma, Pancreatic Ductal/diagnostic imaging , Carcinoma, Pancreatic Ductal/surgery , Humans , Infant , Pancreatic Neoplasms/diagnostic imaging , Pancreatic Neoplasms/surgery , Retrospective StudiesSubject(s)
Attitude to Health , Health Policy , Obesity/prevention & control , Personal Autonomy , Weight Gain , HumansABSTRACT
Social buffering is characterized by attenuation of stress in the presence of others, with supportive individuals providing superior buffering. We were interested in learning if the implied presence of a supportive entity, God, would reduce acute stress. Participants were randomly assigned to one of three conditions: prayer, encouraging self-talk, and control. They were subsequently placed in a stressful situation. Self ratings of stress were lower among the prayer and self-talk conditions relative to controls. Systolic and diastolic blood pressures only among those who prayed were lower than controls; however, prayer and self-talk did not differ. Prayer alone did not significantly reduce stress, perhaps because the majority of students in the prayer condition did not consider reading a prayer to constitute praying.