RESUMEN
A blood test that enables surveillance for early-stage pancreatic ductal adenocarcinoma (PDAC) is an urgent need. Independent laboratories have reported PDAC biomarkers that could improve biomarker performance over CA19-9 alone, but the performance of the previously reported biomarkers in combination is not known. Therefore, we conducted a coordinated case/control study across multiple laboratories using common sets of blinded training and validation samples (132 and 295 plasma samples, respectively) from PDAC patients and non-PDAC control subjects representing conditions under which surveillance occurs. We analyzed the training set to identify candidate biomarker combination panels using biomarkers across laboratories, and we applied the fixed panels to the validation set. The panels identified in the training set, CA19-9 with CA199.STRA, LRG1, TIMP-1, TGM2, THSP2, ANG, and MUC16.STRA, achieved consistent performance in the validation set. The panel of CA19-9 with the glycan biomarker CA199.STRA improved sensitivity from 0.44 with 0.98 specificity for CA19-9 alone to 0.71 with 0.98 specificity (p < 0.001, 1000-fold bootstrap). Similarly, CA19-9 combined with the protein biomarker LRG1 and CA199.STRA improved specificity from 0.16 with 0.94 sensitivity for CA19-9 to 0.65 with 0.89 sensitivity (p < 0.001, 1000-fold bootstrap). We further validated significantly improved performance using biomarker panels that did not include CA19-9. This study establishes the effectiveness of a coordinated study of previously discovered biomarkers and identified panels of those biomarkers that significantly increased the sensitivity and specificity of early-stage PDAC detection in a rigorous validation trial.
RESUMEN
PURPOSE: An effective blood-based test for pancreatic cancer (PC) screening has remained elusive. The IMMray PanCan-d is the first commercially available blood-based test specifically designed for early detection of PC; however, outcomes from its use in clinical practice have not been reported. METHODS: We performed a blinded spike-in study of 100 individuals who had an IMMray PanCan-d test, including 94 high-risk individuals (HRIs) undergoing PC surveillance and six individuals with known PC. Specimens were processed blindly following the commercial laboratory's standardized operating procedure. Positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS: Cohort characteristics included a median age of 63 (IQR, 55-70) years, 57% female, 96% non-Hispanic White, 57% with a pathogenic variant in a PC risk gene (BRCA2 most commonly-18%), and 83% with a family history of PC. Among IMMray PanCan-d results from 94 HRIs undergoing PC surveillance, there was one positive (1%), seven borderlines (7%), 73 negatives (78%), and 13 tests not performed because of low CA19-9 expression (14%). No PC was diagnosed among these HRIs; however, there were two sub-cm pancreatic neuroendocrine tumors, seven clinically diagnosed side branch intraductal papillary mucinous neoplasms ≥1 cm, and a sub-cm solid mass with indeterminate cytology requiring close follow-up; all these individuals had negative IMMray PanCan-d tests. Of the six spiked-in PCs, four (67%) yielded a positive and two (33%) yielded a negative. With an estimated disease prevalence of 2%, the PPV and NPV are 52% and 99%, respectively, if borderline results are considered negative and 12% and 99%, respectively, if borderline tests are considered positive. CONCLUSION: In clinical practice, IMMray PanCan-d has a robust NPV; however, PPV is dramatically influenced by whether borderline results are characterized as a positive or negative result.
