Circulating tumor cells in metastatic breast cancer patients treated with immune checkpoint inhibitors - a biomarker analysis of the ALICE and ICON trials.

Immune checkpoint inhibitors (ICIs) have been introduced in breast cancer (BC) treatment and better biomarkers are needed to predict benefit. Circulating tumor cells (CTCs) are prognostic in BC, but knowledge is limited on CTCs in the context of ICI therapy. In this study, serial sampling of CTCs (CellSearch system) was evaluated in 82 patients with metastatic BC enrolled in two randomized trials investigating ICI plus chemotherapy. Programmed death-ligand 1 (PD-L1) expression on CTCs was also measured. Patients with ≥ 2 CTCs per 7.5 mL at baseline had gene expression profiles in tumor suggestive of increased T-cell activity, including increased tumor inflammation signature (TIS) in both triple-negative (P = 0.010) and hormone receptor-positive (P = 0.024) disease. Patients with luminal A BC had higher CTC levels. The association between CTC status and outcome was most apparent 4 weeks into therapy. PD-L1 expression in CTCs was observed in 6/17 CTC-positive patients and was associated with inferior survival. In conclusion, our study indicates that CTC numbers may inform on tumor immune composition, as well as prognosis. These findings suggest a potential of using CTCs as an accessible biomarker source in BC patients treated with immunotherapy.

Preoperative CTC-Detection by CellSearch® Is Associated with Early Distant Metastasis and Impaired Survival in Resected Pancreatic Cancer.

In patients with presumed pancreatic ductal adenocarcinoma (PDAC), biomarkers that may open for personalised, risk-adapted treatment are lacking. The study analysed the impact of CTCs-presence on the patterns of recurrence and survival in 98 patients resected for PDAC with 5-10 years of follow-up. Preoperative samples were analysed by the CellSearch® system for EpCAM+/DAPI+/CK+/CD45-CTCs. CTCs were detected in 7 of the 98 patients. CTCs predicted a significantly shorter median disease-free survival (DFS) of 3.3 vs. 9.2 months and a median cancer specific survival (CSS)of 6.3 vs. 18.5 months. Relapse status was confirmed by imaging for 87 patients. Of these, 58 patients developed distant metastases (DM) and 29 developed isolated local recurrence (ILR) as the first sign of cancer relapse. All patients with CTCs experienced DM. pN-status and histological grade >2 were other independent risk factors for DM, but only CTCs predicted significantly shorter cancer-specific, disease-free and post-recurrence survival. Preoperative parameters did not affect clinical outcome. We conclude that CTC presence in resected PDAC patients predicted early distant metastasis and impaired survival. Preoperative CTCs alone or in combination with histopathological factors may guide initial treatment decisions in patients with resectable PDAC in the future.

Circulating Tumor Cells are an Independent Predictor of Shorter Survival in Patients Undergoing Resection for Pancreatic and Periampullary Adenocarcinoma.

OBJECTIVE: We evaluated the prognostic impact of circulating tumor cells (CTCs) for patients with presumed resectable pancreatic and periampullary cancers. SUMMARY OF BACKGROUND DATA: Initial treatment decisions for this group are currently taken without a reliable prognostic marker. The CellSearch system allows standardized CTC-testing and has shown excellent specificity and prognostic value in other applications. METHODS: Preoperative blood samples from 242 patients between September 2009 and December 2014 were analyzed. One hundred seventy-nine patients underwent tumor resection, of whom 30 with stage-I tumors and duodenal cancer were assigned to the low-risk group, and the others to the high-risk group. Further 33 had advanced disease, 30 benign histology. Observation ended in December 2016. Cancer-specific survival (CSS) and disease-free survival (DFS) were calculated by log-rank and Cox regression. RESULTS: CTCs (CTC-positive; ≥1 CTC/7.5 mL) were detected in 6.8% (10/147) of the high-risk patients and 6.2% (2/33) with advanced disease. No CTCs (CTC-negative) were detected in the low-risk patients or benign disease. In high-risk patients, median CSS for CTC-positive versus CTC-negative was 8.1 versus 20.0 months (P < 0.0001), and DFS 4.0 versus 10.5 months (P < 0.001). Median CSS in advanced disease was 7.7 months. Univariate hazard ratio (HR) of CTC-positivity was 3.4 (P < 0.001). In multivariable analysis, CTC-status remained independent (HR: 2.4, P = 0.009) when corrected for histological type (HR: 2.7, P = 0.030), nodal status (HR: 1.7, P = 0.016), and vascular infiltration (HR: 1.7, P = 0.001). CONCLUSION: Patients testing CTC-positive preoperatively showed a detrimental outcome despite successful tumor resections. Although the low CTC-rate seems a limiting factor, results indicate high specificity. Thus, preoperative analysis of CTCs by this test may guide treatment decisions and warrants further testing in clinical trials.

Detection of Circulating Tumor Cells at Surgery and at Follow-Up Assessment to Predict Survival After Two-Stage Liver Resection of Colorectal Liver Metastases.

BACKGROUND: The presence of circulating tumor cells (CTCs) is negatively associated with survival after resection of colorectal liver metastases (CLM). The current study aimed to determine the prognostic value of CTCs and disseminated tumor cells (DTCs) at the time of surgery and the prognostic value of CTCs at follow-up assessment, for patients scheduled to undergo two-stage hepatectomy with portal vein embolization (PVE) for CLM. METHODS: Samples were collected at surgery (blood and bone marrow) and at follow-up assessment (blood) for the period 2008 through 2011. In this study, CTCs were detected with the CellSearch system, and DTCs were detected using standard immunocytochemical analysis. RESULTS: Of 24 patients, 18 completed both stages, and no patients were lost to follow-up. The median overall survival (OS) was 37 months, and the median recurrence-free survival (RFS) was 7 months. At surgery, CTCs were found in nine patients (38 %), and their presence was associated with reduced OS (p < 0.001) and RFS (p = 0.006). Follow-up CTC status was available for 11 patients. All eight patients with positive CTC status experienced recurrence. Two of three patients with negative CTC status remained recurrence free. In seven patients (32 %), DTCs were detected but were not associated with OS or RFS. CONCLUSIONS: The presence of CTCs at surgery is associated with worse OS and RFS for patients undergoing two-stage hepatectomy with PVE for CLM. Analysis of CTCs should be explored further for their potential to assist in treatment decisions and monitoring for CLM patients.