BACKGROUND: Recent advances in perioperative immunotherapies have led to a new era in the perioperative treatment of resectable, non-small cell lung cancer (NSCLC). Although the choice of neoadjuvant, adjuvant or perioperative immunotherapy remains controversial, few reports have compared programmed death ligand-1 (PD-L1) expression as a biomarker between preoperative biopsy specimens and surgical specimens. METHODS: We retrospectively reviewed consecutive patients with NSCLC whose preoperative biopsy specimens and surgical specimens were tested for PD-L1 (22C3) and PD-L1 (SP263), respectively, from June 2022 to February 2024. The three categorical classifications of PD-L1 expression (negative [<
1%], low [1-49%], and high [≥50%]) were compared between the two tests. RESULTS: Of the 33 patients, 13 patients had negative PD-L1 expression, 9 patients had low PD-L1 expression and 11 patients had high PD-L1 expression with preoperative biopsy specimens, while 18 patients had negative PD-L1 expression, 10 patients had low PD-L1 expression and 5 patients had high PD-L1 expression with surgical specimens. The concordance rate for the three categorical classifications of PD-L1 expression between the preoperative biopsy specimens and surgical specimens was 57.6%. CONCLUSIONS: PD-L1 expression may differ between preoperative biopsy specimens and surgical specimens. PD-L1 expression evaluated using small biopsy specimens may be largely influenced by chance due to intra-tumoral heterogeneity.