Clinical utility of circulating genetically anormal cells in stage I small-cell lung cancer diagnosis.

Abstract

e20581 Background: Small-cell lung cancer (SCLC) is an aggressive disease with rapid progression rate and high metastatic potential that accounts for 15% of all lung cancers. Early-stage SCLC is usually asymptomatic; therefore, the majority of the SCLC patients were diagnosed in advanced stages. Although some radiological features were reported with advanced stages SCLC by CT scans, diagnosis of early stages SCLC from CT images has remained challenging since the radiological features are not distinct. Neuron-specific enolase (NSE) is commonly used in the clinical setting as a biomarker for SCLC, but the sensitivity of the test did not meet the needs. Here, we proposed a study using Circulating Genetically Abnormal Cells (CAC) to improve the diagnosis rate of SCLC in the early stages. Methods: A series of 26 stage I SCLC patients were enrolled from October 2019 to October 2020. All participants were having newly discovered pulmonary nodules ≤ 30mm when enrolled in the study, with no previous cancer history. Before the histopathological examination, 10 ml of peripheral blood were collected from each patient for CAC test, by using a 4 color FISH–based assay to detect the genetic abnormalities of 3p22.1, 3q29, 10q22.3, and CEP10 in the chromosome. Besides, NSE was performed on all participants. Both tests were intended to evaluate the malignant risk of lung nodules. Results: Confirmed by histopathological exam, 69% patients were diagnosed with SCLC located on the central part of the lung, and 31% patients were found to have peripheral-type SCLC. 88% of the patients in the overall cohort were smokers or past smokers, and only 12% participants had a family history of cancer. For Immunohistochemistry tests, the numbers of participants with positive CD56, TTF-1, CgA, CK, Syn and Ki-67 ≥ 60% are 65%, 58%, 12%, 42%, 50% and 69%, respectively. For diagnostic performance, the sensitivity of CAC in the over-all cohort is 73.08% (95%CI: 52.21%-88.43%), compared with 50.00% (95%CI: 29.93%- 70.07%) for NSE. CAC has achieved 77.78% (95%CI: 52.36% - 93.59%) and 62.5% (95%CI：24.49% - 91.48%) sensitivity in the centra and peripheral group. For NSE, the sensitivity of these two groups were 55.56% (95%CI: 30.76% - 78.47%) and 37.5% (95%CI: 8.52% - 75.51%). Conclusions: Compared with NSE, CAC is more sensitive to stage I SCLC, especially for SCLC that arising in central locations. This non-invasive method can be a complementary diagnostic tool with LDCT for smokers aged ≥65 with newly discovered pulmonary nodules. Clinical trial information: ChiCTR1900026233.