Clinical value of circulating endothelial cell levels in metastatic colorectal cancer patients treated with first-line chemotherapy and bevacizumab.

BACKGROUND: We investigated whether circulating endothelial cells (CECs) predict clinical outcome of first-line chemotherapy and bevacizumab in metastatic colorectal cancer (mCRC) patients. PATIENTS AND METHODS: In a substudy of the randomized phase II FNCLCC ACCORD 13/0503 trial, CECs (CD45- CD31+ CD146+ 7-amino-actinomycin- cells) were enumerated in 99 patients by four-color flow cytometry at baseline and after one cycle of treatment. We correlated CEC levels with objective response rate (ORR), 6-month progression-free survival (PFS) rate (primary end point of the trial), PFS, and overall survival (OS). Multivariate analyses of potential prognostic factors, including CEC counts and Köhne score, were carried out. RESULTS: By multivariate analysis, high baseline CEC levels were the only independent prognostic factor for 6-month PFS rate (P < 0.01) and were independently associated with worse PFS (P = 0.02). High CEC levels after one cycle were the only independent prognostic factor for ORR (P = 0.03). High CEC levels at both time points independently predicted worse ORR (P = 0.025), 6-month PFS rate (P = 0.007), and PFS (P = 0.02). Köhne score was the only variable associated with OS. CONCLUSION: CEC levels at baseline and after one treatment cycle may independently predict ORR and PFS in mCRC patients starting first-line bevacizumab and chemotherapy.

A direct comparison of CellSearch and ISET for circulating tumour-cell detection in patients with metastatic carcinomas.

BACKGROUND: Circulating tumour cells (CTCs) can provide information on patient prognosis and treatment efficacy. However, there is no universal method to detect CTC currently available. Here, we compared the performance of two CTC detection systems based on the expression of the EpCAM antigen (CellSearch assay) or on cell size (ISET assay). METHODS: Circulating tumour cells were enumerated in 60 patients with metastatic carcinomas of breast, prostate and lung origins using CellSearch according to the manufacturer's protocol and ISET by studying cytomorphology and immunolabelling with anti-cytokeratin or lineage-specific antibodies. RESULTS: Concordant results were obtained in 55% (11 out of 20) of the patients with breast cancer, in 60% (12 out of 20) of the patients with prostate cancer and in only 20% (4 out of 20) of lung cancer patients. CONCLUSION: Our results highlight important discrepancies between the numbers of CTC enumerated by both techniques. These differences depend mostly on the tumour type. These results suggest that technologies limiting CTC capture to EpCAM-positive cells, may present important limitations, especially in patients with metastatic lung carcinoma.

Levels of circulating CD45(dim)CD34(+)VEGFR2(+) progenitor cells correlate with outcome in metastatic renal cell carcinoma patients treated with tyrosine kinase inhibitors.

BACKGROUND: Predicting the efficacy of antiangiogenic therapy would be of clinical value in patients (pts) with metastatic renal cell carcinoma (mRCC). We tested the hypothesis that circulating endothelial cell (CEC), bone marrow-derived CD45(dim)CD34(+)VEGFR2(+) progenitor cell or plasma angiogenic factor levels are associated with clinical outcome in mRCC pts undergoing treatment with tyrosine kinase inhibitors (TKI). METHODS: Fifty-five mRCC pts were prospectively monitored at baseline (day 1) and day 14 during treatment (46 pts received sunitinib and 9 pts received sorafenib). Circulating endothelial cells (CD45(-)CD31(+)CD146(+)7-amino-actinomycin (7AAD)(-) cells) were measured in 1 ml whole blood using four-color flow cytometry (FCM). Circulating CD45(dim)CD34(+)VEGFR2(+)7AAD(-) progenitor cells were measured in progenitor-enriched fractions by four-color FCM. Plasma VEGF, sVEGFR2, SDF-1α and sVCAM-1 levels were determined by ELISA. Correlations between baseline CEC, CD45(dim)CD34(+)VEGFR2(+)7AAD(-) progenitor cells, plasma factors, as well as day 1-day 14 changes in CEC, CD45(dim)CD34(+)VEGFR2(+)7AAD(-) progenitor, plasma factor levels, and response to TKI, progression-free survival (PFS) and overall survival (OS) were examined. RESULTS: No significant correlation between markers and response to TKI was observed. No association between baseline CEC, plasma VEGF, sVEGFR-2, SDF-1α, sVCAM-1 levels with PFS and OS was observed. However, baseline CD45(dim)CD34(+)VEGFR2(+)7AAD(-) progenitor cell levels were associated with PFS (P=0.01) and OS (P=0.006). Changes in this population and in SDF-1α levels between day 1 and day 14 were associated with PFS (P=0.03, P=0.002). Changes in VEGF and SDF-1α levels were associated with OS (P=0.02, P=0.007). CONCLUSION: Monitoring CD45(dim)CD34(+)VEGFR2(+) progenitor cells, plasma VEGF and SDF-1α levels could be of clinical interest in TKI-treated mRCC pts to predict outcome.