Clustered Circulating Tumor Cells as a Predictor of Adjuvant-chemotherapy Efficacy in Lung Cancer.

Abstract

Surrogate markers of minimal residual disease primarily include cell-free tumor DNA and circulating tumor cells. Cell-free tumor DNA might aid precise decision-making regarding who should receive adjuvant chemotherapy. However, there are no relevant reports on circulating tumor cells. Therefore, we aimed to verify whether perioperative clustered circulating tumour cells identification is a predictor of therapeutic efficacy in non-small cell lung cancer adjuvant chemotherapy. Circulating tumor cells were diagnosed under light microscopy using a size selection method in 128 patients with clinical stage I/II non-small cell lung cancer around surgery. The main endpoint was recurrence-free survival, and the effect of adjuvant chemotherapy was verified in both groups based on perioperative clustered circulating tumor cell identification. In total, 49 and 79 patients were included in the clustered circulating tumor cell-positive and clustered circulating tumor cell-negative patient groups, respectively. In the clustered circulating tumor cell-positive patient group, adjuvant chemotherapy was performed in 18 patients (2-year recurrence-free survival rate, 71.8%). However, the 2-year recurrence-free survival rate was 36.3% in 31 patients who did not receive adjuvant chemotherapy (P < .01). In the clustered circulating tumor cell-negative patient group, adjuvant chemotherapy was provided in 11 patients (2-year recurrence-free survival rate, 90.9%). However, 68 patients did not receive adjuvant chemotherapy (2-year recurrence-free survival rate, 94.9%) (not significant). In surgical cases of clinical stage I/II non-small cell lung cancer, patients with perioperative clustered circulating tumor cells had a poor prognosis, but adjuvant chemotherapy improved their prognosis.