Biopsy and Re-Biopsy for PD-L1 expression in NSCLC. Association Between PD-L1 and Checkpoint Inhibitor Efficacy through treatment in NSCLC. A Pilot Study.

INTRODUCTION Lung cancer is diagnosed at a late stage due to lack of early disease symptoms. Therefore an efficient treatment is necessary for prolonged disease free survival. PATIENTS AND METHODS In our study we recruited 124 patients NSCLC patients with adenocarcinoma and squamus cell carcinoma. All recuited patients had Programmed death-ligand 1 expression ≥50 (PD-L1)with DAKO technique. Immunotherapy was administered with as first line treatment. Re-biopsies were performed in the main lung lesion every four months with the restaging of the patient and also in the metastastic sites in other organs that occurred during treatment. PD-L1 expressed was evaluated in the biopsies of the metastatic sites. RESULTS It appears thereafter that the PD-L1 expression could easily be claimed as a promising bio-index with a cut-off value 65, below which a negative prognosis of the disease progress will be evident and above that value a positive continuation of the disease will be prominent. CONCLUSION The findings of this study suggest that the PD-L1-65 index works adequately either concerning the neo-metastatic sites or the patient disease responses. Re-biopsies in new metastastic sites are necessary since we probably have a new cancer and chemotherapy should be added. More studies should confirm are results and change the NSCLC treatment approach of these patients.