Circulating tumour cells (CTCs) are reported to be predictive for prognosis and response to treatment in advanced lung cancer. However, the clinical utility of the CTCs detection remains unknown for early stage lung cancer as the number of CTCs is reported as low, providing challenges in identification. We have evaluated diagnostic performance of filtration-based technology using cytomorphologic criteria in patients undergoing surgery for lung cancer.
Material and methods
We processed blood from 76 patients undergoing surgery for known or suspected lung cancer using ScreenCell® Cyto filter devices. Captured cells were stained using haematoxylin and eosin and independently assessed by two pathologists for the presence of atypical cells suspicious for cancer. Diagnostic performance was evaluated against pathologist reported diagnoses of cancer from surgically obtained specimens.
Cancer was diagnosed in 57 patients (77.0%), including 32 with primary lung cancer (56.1%). The proportion of patients with early stage primary lung cancer in which CTCs were identified was 18 and 21 (56.3% and 65.6%, respectively) as reported by two pathologists. The agreement between the pathologists was 77.0% corresponding to a kappa-statistic of 53.7% indicating moderate agreement. No significant differences were found for the percentage of CTCs for primary and metastatic cancer as well as for cancer stages. On sensitivity weighted analysis, a sensitivity and specificity were 71.9% (95% CI 60.5–83.0) and 52.9% (95% CI 31.1–77.0), respectively. On specificity weighted analysis, a sensitivity and specificity were 50.9% (95% CI 39.3–64.4) and 82.4% (60.4–96.2), respectively.
The performance of the tested filter-based antibody-independent technology to capture CTCs using standard cytomorphologic criteria provides the potential of a diagnostic blood test for lung cancer.