F-059
THE DIAGNOSTIC SIGNIFICANCE OF CIRCULATING TUMOUR CELLS IN DIAGNOSING LUNG CANCER: CORRELATION WITH CLINICAL AND CYTO-MORPHOLOGICAL FEATURES

Abstract

Objectives: In lung cancer there still remains controversy on the incidence and diagnostic utility of circulating tumour cells (CTCs). We aimed to evaluate the performance of CTCs in differentiating benign from malignant lung lesions and to compare the cyto-morphological features of CTCs with cancer cells obtained from preoperative biopsies and from surgical pathological specimens.

Methods: Eighty-one patients with radiological lung lesions were prospectively enrolled. Before diagnostic invasive examinations, CTCs were captured from 7.5-ml peripheral blood samples with a ScreenCell system that used a filtre of 7.5 µm average pore size. The results, expressed as number of CTCs/7.5 ml, were correlated with definitive diagnosis and the cyto-morphological features of CTCs compared with the results of preoperative biopsies and pathological specimens of resected patients.

Results: Seventy-seven patients completed the study. Of these 60 (78%) had primary lung cancer (30 adenocarcinoma, 27 squamous and 3 large cell carcinoma). CTC count was higher in malignant than in benign lesions (3.8 ± 3.3 vs 0.3 ± 0.8; P = 0.0001; t-test). ANOVA test showed that Stage IV presented a higher CTC count than stage III (P < 0.05), II (P < 0.05) and I (P < 0.05). ROC curve (AUC: 0.896; 95% CI 0.805 to 0.954; P < 0.0001) showed that sensitivity, specificity, PPV and NPV to diagnose cancer were 78% (95% CI 65.8-87.9); 88% (95% CI 63.6-98.5); 95% (95% CI 86.0-99.5); and 53% (95% CI 33.5-72.8) in patients with ≥1 CTC count; a specificity of 100% (95% CI 80.5-100%) was obtained with a CTC count ≥3. In 42/60 (70%) malignant lesions the CTCs diagnosed the precise subtype of non-small-cell lung cancer (NSCLC) i.e. adenocarcinoma, squamous carcinoma, etc. When the CTCs were compared with biopsy or surgical specimen results, a correlation of 100% was found.

Conclusions: CTCs are promising biomarkers to diagnose lung cancer. If our data are corroborated by larger study, the “liquid biopsy” in the future would substitute the need for painful and often inaccessible “solid biopsies”.

Disclosure: No significant relationships.