Liquid Biopsy for Detection of Pancreaticobiliary Cancers in Suspected Patients by Functional Enrichment and Immunofluorescent Profiling of Circulating Tumor Cells and their Clusters

Background Circulating tumor cells (CTCs) have historically been used for prognostication in oncology. We evaluate performance of liquid biopsy CTC assay as a diagnostic tool in suspected pancreaticobiliary cancers. The assay utilises functional enrichment of CTCs followed by immunofluorescent profiling of organ specific markers. Methods Multicentric case control study was followed by a prospective observational study. Adult patients undergoing tissue sampling for suspected pancreaticobiliary cancer were included in the studies. Blood samples for TruBlood® CTC assay were drawn before tissue sampling. Patients with a prior cancer treatment or cancer history were excluded. CTCs and their clusters were harvested by a unique functional enrichment method which is label-free, size independent and non-mechanical. The CTCs then underwent immunofluorescent profiling for CA19.9, Maspin, EpCAM, CK and CD45, blinded to the tissue histopathological diagnosis. TruBlood® malignant or non-malignant predictions were compared with tissue diagnoses to establish the sensitivity and specificity. Results The case-control study evaluated 360 participants including 188 cases diagnosed with pancreaticobiliary cancer and 172 healthy individuals. A subsequent prospective observational study included 88 individuals with suspicion of pancreaticobiliary malignancy. The test had 95.9% overall sensitivity (95% CI: 86.0% - 99.5%) and 92.3% specificity (95% CI: 79.13% to 98.38%) to differentiate pancreaticobiliary cancers (PBC) (n = 49) from benign PB conditions (n = 39). Conclusions The high accuracy of the CTC based TruBlood test demonstrates its potential clinical application as a diagnostic tool to assist effective detection of pancreaticobiliary cancers when tissue sampling is unviable or inconclusive. A confirmational prospective interventional studiy in patients with suspicion of pancreaticobiliary malignancy including those with unavailability of tissue diagnosis is warranted.