Circulating Tumor Cells Allow Early Diagnosis of Lung Cancer

CTCs were identified by cytomorphological analysis and characterized by studying their expression of epithelial and mesenchymal markers.

CTC detection was performed using The Isolation by Size of Epithelial Tumor cells (ISET) technology (Rarecells Diagnostics; Paris, France). The ISET method is a blood filtration-based approach, which enriches on a polycarbonate membrane cells larger than eight micrometers. The membrane was processed both for immunocytochemistry and for May Grünwald Giemsa (MGG) staining for cytological analysis. Immunocytochemistry was performed using double immunolabeling. Using ISET, patients were considered positive for CTCs based on cytopathological analysis of the isolated cells and detection of cells with characteristic malignant features determined according to previously defined criteria.

CTCs were detected in 5 of the 168 patients (3%) of COPD patients. Isolated cells with benign cytomorphological features were detected by ISET in 3 out of 168 patients (1.8%) of COPD patients. None of these three patients and none of the other 160 patients with COPD, and with no pathological cells at baseline in the blood, were shown to develop a lung nodule, as demonstrated by a yearly computerized tomography (CT)-scan during the subsequent follow-up starting with the first blood filtration.

The authors concluded that a sensitive and diagnostic CTC detection approach can find CTCs in patients “at risk” of developing lung cancer without a detectable nodule by CT scan. A small fraction of COPD patients were found to have CTCs one to four years before identification of a lung nodule by imaging. In five patients, the lung cancer was diagnosed at an early stage (IA) allowing prompt surgical resection; they were then shown to be without tumor recurrence and without CTCs 16 months after surgery. The study was published on October 31, 2014, in the journal Public Library of Science ONE.

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