Validation of a Pancreatic Cancer Detection Test in New-Onset Diabetes Using Cell-Free DNA 5-Hydroxymethylation Signatures
BACKGROUND Pancreatic cancer (PaC) has poor (10%) 5–year overall survival, largely due to predominant late-stage diagnosis. Patients with new-onset diabetes (NOD) are at a six– to eightfold increased risk for PaC. We developed a pancreatic cancer detection test for the use in a clinical setting that employs a logistic regression model based on 5–hydroxymethylcytosine (5hmC) profiling of cell-free DNA (cfDNA). METHODS: cfDNA was isolated from plasma from 89 subjects with PaC and 596 case–control non–cancer subjects, and 5hmC libraries were generated and sequenced. These data coupled with machine–learning, were used to generate a predictive model for PaC detection, which was independently validated on 79 subjects with PaC, 163 non–cancer subjects, and 506 patients with non–PaC cancers. RESULTS: The area under the receiver operating characteristic curve for PaC classification was 0.93 across the training data. Training sensitivity was 58.4% (95% confidence interval [CI]: 47.5–68.6) after setting a classification probability threshold that resulted in 98% (95% CI: 96.5–99) specificity. The independent validation dataset sensitivity and specificity were 51.9% (95% CI: 40.4–63.3) and 100.0% (95% CI: 97.8–100.0), respectively. Early–stage (stage I and II) PaC detection was 47.6% (95% CI: 23%–58%) and 39.4% (95% CI: 32%–64%) in the training and independent validation datasets, respectively. Sensitivity and specificity in NOD patients were 55.2% [95% CI: 35.7–73.6] and 98.4% [95% CI: 91.3–100.0], respectively. The PaC signal was identified in intraductal papillary mucinous neoplasm (64%), pancreatitis (56%), and non-PaC cancers (17%). CONCLUSIONS: The pancreatic cancer detection assay showed robust performance in the tested cohorts and carries the promise of becoming an essential clinical tool to enable early detection in high–risk NOD patients.