Programmed Cell Death Ligand 1-Expressing Circulating Tumor Cells: A New Prognostic Biomarker in Non-Small Cell Lung Cancer.

BACKGROUND: In non-small cell lung cancer (NSCLC), analysis of programmed cell death ligand 1 (PD-L1) expression in circulating tumor cells (CTCs) is a potential alternative to overcome the problems linked to the tumor biopsy spatiotemporal heterogeneity. However, the prognostic significance of PD-L1-positive [PD-L1(+)] CTCs remains controversial. METHODS: We prospectively evaluated the correlation with clinicopathological variables and prognostic value of PD-L1(+) CTCs, detected with the FDA-cleared CellSearch® system, in 54 patients with advanced NSCLC. RESULTS: We detected CTCs and PD-L1(+) CTCs in 43.4% and 9.4% of patients with NSCLC. PD-L1 expression concordance between tumor tissue and CTCs was low (54%). The presence of PD-L1(+) CTC correlated with the absence of gene alterations in tumor tissue and with poor prognosis-related biological variables (anemia, hyponatremia, increased lactate dehydrogenase). In univariate analysis, absence of gene alterations, number of metastatic sites, prior systemic therapies, and presence of CTCs and PD-L1(+) CTCs were associated with worse overall survival, whereas PD-L1 expression in tumor tissue was not. In multivariate analysis, squamous cell carcinoma histology, number of prior systemic treatments, and the presence of CTC were significantly associated with overall survival. Survival was worse in patients with PD-L1(+) CTCs than in patients with PD-L1-negative CTC or without any CTC. CONCLUSIONS: Our study suggests that the presence of PD-L1(+) CTCs is associated with poor prognosis in patients with advanced NSCLC. Studies with larger samples are needed to confirm our results and to determine how PD-L1(+) CTC detection could help to predict the response or resistance to anti-PD-1/PD-L1 therapies.Clinical trial registration NCT02866149.

Assessment of the Efficacy and Clinical Utility of Different Circulating Tumor Cell (CTC) Detection Assays in Patients with Chemotherapy-Naïve Advanced or Metastatic Non-Small Cell Lung Cancer (NSCLC).

We herein investigated the detection frequency and clinical relevance of circulating tumor cells (CTCs) in chemotherapy-naïve stage IIIB/IV non-small cell lung cancer (NSCLC), by using the CellSearch and real-time CEACAM5mRNA assays. Blood samples from 43 patients were obtained at different time points during first-line chemotherapy. CellSearch revealed the detection of ≥1 CTCs in 41.9%, 40.9%, and 16.7% of patients at baseline, post-1st, and post-2nd treatment cycle, respectively, and of ≥5 CTCs in 11.6%, 9.1%, and 5.6%, respectively. CEACAM5mRNA+ CTCs were detected in 29.3% and 16% of patients pre- and post-treatment, respectively. The positivity concordance between the two assays was 2.2%. CTC-detection by CellSearch (≥5 CTCs: p = 0.004), CEACAM5mRNA (p = 0.010), or by any assay (p = 0.000) was associated with disease progression. Reduced survival was demonstrated for patients harboring ≥5 CTCs (progression-free survival; PFS: p = 0.000; overall survival; OS: p = 0.009), CEACAM5mRNA+ CTCs (PFS: p = 0.043; OS: p = 0.039), and CTCs by any assay (PFS: p = 0.005; OS: p = 0.006, respectively). CTC-detection by any assay independently predicted for increased risk of relapse (hazard ratio; HR: 3.496; p = 0.001) and death (HR: 2.866; p = 0.008). CellSearch-positivity either pre-, post-1st, or post-2nd cycle, was predictive for shorter PFS (p = 0.036) compared to negativity in all time points. Persistent CEACAM5mRNA-positivity pre- and post-treatment was associated with reduced PFS (p = 0.036) and OS (p = 0.026). In conclusion, CTC detection and monitoring using the CellSearch and CEACAM5mRNA assays provides valuable and complementary clinical information for chemo-naïve advanced or metastatic NSCLC.

Circulating tumor cells as a preoperative risk marker for occult metastases in patients with resectable cholangiocarcinoma.

Cholangiocarcinoma (CCA) is an aggressive tumor associated with a high rate of recurrence after resection. An important risk factor for recurrence is the presence of occult metasta-ses, which are not radiologically detectable at the time of diagnosis. There are currently no biomarkers for the preoperative assessment of micrometastases. A previous study demonstrated the prognostic relevance of circulating tumor cells (CTC) in patients with advanced CCA but the potential of CTCs as a preoperative marker for detecting occult metastases has not been investigated so far. In this two-phase study, we first recruited a cohort of 27 patients with histologically proven, metastatic CCA or gallbladder cancer (GBCA) to assess feasibility (feasibility cohort, FC). CTCs were measured in the peripheral blood using the CellSearch System (CSS) between October 2012 and January 2017. Subsequently, in 11 patients undergoing curative-intended resection for CCA (intrahepatic CCA: n =4; extrahepatic CCA n= 6; gallbladder cancer: n=1), peripheral and central venous blood specimens were obtained to improve detection rate by simultaneous measurement and to elucidate distribution of CTCs in different venous compartments. Presence of CTCs detection was correlated with postoperative TNM-status. In the FC, CTCs (range 1-3 cells, median: 1) were detected in 40% (11/27) patients and were signifi-cantly associated with worse overall survival (hazard ratio: 3.59; 95% CI: 1.79- 7.1; p = 0.04). By combined peripheral and central measurement, CTC detection was increased to 54% (6/11) in the resection cohort (RC) and was associated with metastases that were only identified during the surgical procedure (peritoneal carcinoma: n = 1; infiltration of the duodenum: n = 1) or immediately after surgery (evidence of pulmonary metastases by CT scan two days after resection, not evident on initial tumor staging prior resection). Taken together, in this single center pilot study, we demonstrated that CTCs are detectable in CCA patients and are associated with significantly impaired survival in patients at metastatic stage. Detection rate prior to surgery was improved to >50% by combined peripheral and central measurement. Moreover, preoperative CTC detection may indicate existing metastases and could help to stratify patients more accurately.

Clinical Relevance of Viable Circulating Tumor Cells in Patients with Metastatic Colorectal Cancer: The COLOSPOT Prospective Study.

BACKGROUND: Circulating tumor cells (CTCs) allow the real-time monitoring of tumor course and treatment response. This prospective multicenter study evaluates and compares the early predictive value of CTC enumeration with EPISPOT, a functional assay that detects only viable CTCs, and with the CellSearch® system in patients with metastatic colorectal cancer (mCRC). METHODS: Treatment-naive patients with mCRC and measurable disease (RECIST criteria 1.1) received FOLFIRI-bevacizumab until progression or unacceptable toxicity. CTCs in peripheral blood were enumerated at D0, D14, D28, D42, and D56 (EPISPOT assay) and at D0 and D28 (CellSearch® system). Progression-free survival (PFS) and overall survival (OS) were assessed with the Kaplan-Meier method and log-rank test. RESULTS: With the EPISPOT assay, at least 1 viable CTC was detected in 21% (D0), 15% (D14), 12% (D28), 10% (D42), and 12% (D56) of 155 patients. PFS and OS were shorter in patients who remained positive, with viable CTCs between D0 and D28 compared with the other patients (PFS = 7.36 vs. 9.43 months, p = 0.0161 and OS = 25.99 vs. 13.83 months, p = 0.0178). The prognostic and predictive values of ≥3 CTCs (CellSearch® system) were confirmed. CONCLUSIONS: CTC detection at D28 and the D0-D28 CTC dynamics evaluated with the EPISPOT assay were associated with outcomes and may predict response to treatment.

Clinical impact of circulating tumor cells and therapy response in pancreatic cancer.

BACKGROUND: Among gastrointestinal cancers, the prognosis of pancreatic cancer is one of the poorest, with a large number of patients being diagnosed with unresectable tumors at the first visit to a doctor. The aims of the present study were to investigate the circulating tumor cells (CTC) in peripheral blood in order to assess their clinical significance in patients with pancreatic cancer. METHODS: Sixty-five patients with advanced pancreatic cancer were enrolled. Borderline resectable pancreatic tumor patients were 9, and Unresectable patients were 56. The CellSearch system was used to isolate and enumerate CTCs. RESULTS: CTCs were identified in 21 out of 65 patients (32.3%) with only unresectable tumors. The overall survival rate was significantly lower in unresectable patients with than in those without CTCs (P = 0.0051). CTC positivity was significantly higher in patients with than in those without liver metastasis. A multivariate analysis identified the presence or absence of CTCs as an independent prognostic factor. Follow-up blood specimens were obtained from 40 patients treated with chemotherapy or chemoradiotherapy. The incidences of CTC positivity at three months after beginning of treatments in patients with progressive disease and stable disease or a partial response were 45.4% and 24.1%, respectively. The overall survival rate was significantly lower in patients with than in those without CTCs even after treatments (P = 0.045). CONCLUSION: CTC numbers represents a useful tool for predicting prognoses and therapeutic responses to chemotherapy among patients with advanced pancreatic cancer.