Chunxia Su, Caicun Zhou

oncology, shanghai pulmonary hospital

Objective:Targeted therapies have considerablyimproved the prognosis of patients with non-small cell lung cancer (NSCLC).Although not precision enough, RESIST criteria was still the most often usedresponse assessment method to reflecting the clinical benefits. We propose anon-invasive, folate receptor (FR)–based circulating tumor cell (CTC) detectionapproach to interpret treatment response of targeted therapy between baselineand follow-up CTC values in EGFR mutation/ALK translocation advanced NSCLC. 

Method:  One hundred and thirty eight patientswere enrolled in our study. Peripheral blood was analyzed for CTCs enumerationon negative enrichment by immunomagnetic beads. Changes of CTCs levels werecorrelated with radiological response. Sequential analyses were conducted tomonitor CTC signals during therapy and correlate radiological effects withtreatment outcome.

Result: CTCs were detected (≥8.7CTC) in 84.8% ofpatients. Pretreatment and pro-treatment blood samples from all 118 EGFR-mutant(19deltion: 56, L858R: 57, G719x: 3, L861Q: 1, 19 deletion + L858R: 1), 14 ALKtranslocation lung cancer patients and 6 EGFR wild type patients were collected.Of 89 eligible and evaluable patients, baseline CTC counts were not associatedwith response to treatment by RECIST (P=0.353). There is no differencebetween exon 19 deletion and L858R of baseline CTC values. (19deletion: 19.4CTCs, L858R: 20.9 CTCs, P=0.222) The change of CTCs values increasedcorrelation with radiological response (P=0.042) after treatment oftargeted therapy. There is no significant difference between exon 19 deletionand L858R of CTCs values pre and pro EGFR-TKI treatment. (3.32 vs.12.1, P=0.783).

Conclusion: This study confirms the predictive significance of CTCs inpatients with EGFR mutation/ALK translocation NSCLC receiving targeted therapy.The change of CTCs value correlated significantly with radiological response.This strategy may enable non-invasive, specific biomarker assessment method forusing CTC decreases as an early indication of response to targeted therapy andmonitoring in patients undergoing targeted cancer therapies.

Key Words:  Circulating Tumor Cells  Targeted Therapy  Metastati