Abstract
Background:
Anti-PD-(L)1 agents play an important role in the management of NSCLC. PD-L1 analysis by immunohistochemistry is an important biomarker but displays temporospatial heterogeneity. In advanced NSCLC, metabolic parameters tumoural maximum standardised uptake value (SUVmax) and total lesion glycolysis (TLG) of 18F-FDG-PET/CT have been shown to correlate with PD-L1 expression. However, advanced status itself has been associated with high SUVmax and the relationship in early-stage disease has yet to be determined.
Methods:
This retrospective study included NSCLC patients who underwent primary resection at a UK cancer centre. PD-L1 tumour proportion score (TPS) was assessed using the 22C3 pharmDx DAKO assay. Pre-surgical 18F-FDG-PET/CT scans were assessed for metabolic parameters: SUVmax; SUVmean; SUVpeak; SULpeak (lean body mass corrected), metabolic tumour volume (MTV), TLG and SUV-based heterogeneity index (HISUV). 40 cases were assessed by 2 observers to determine interobserver reliability. To determine correlation between metabolic parameters and PD-L1 TPS, unpaired t-test, one-way ANOVA or Kruskall-Wallis tests were applied. Interobserver reliability was determined using intraclass correlation coefficient (ICC).
Results:
Patients (n=100) were grouped by primary tumour PD-L1 TPS of <1% (n=45), 1-49% (n=37) and ≥50% (n=18). There was no statistical difference between PD-L1 TPS groups for primary tumour SUVmax with mean SUVmax of 12.0 (95% CI 10.0-14.0) in PD-L1 <1% group, 14.0 (11.9-16.0) in PD-L1 1-49%, and 12.9 (10.2-15.7) in PD-L1 ≥50% (p=0.38). There was a non-significant trend in correlation with MTV with a mean MTV of 29.86 (19.2-40.6) in PD-L1 <1% group, 24.2 (14.3-34.2) in PD-L1 1-49%, and 15.5 (1.3-29.6) in PD-L1 ≥50% group (p=0.06). There was no significance between PD-L1 subgroups for SUVmean (p=0.48), SUVpeak (p=0.91), SULpeak (p=0.88), TLG (p=0.21) and HISUV (p=0.07). The ICCs between observers for all parameters were excellent (>0.9).
Conclusions:
There was no correlation between primary resected NSCLC 18F-FDG-PET/CT metabolic parameters and PD-L1 TPS. A trend toward significant correlation for MTV and HISUV warrants further investigation. Importantly, we determined that interobserver reliability was excellent.
Anti-PD-(L)1 agents play an important role in the management of NSCLC. PD-L1 analysis by immunohistochemistry is an important biomarker but displays temporospatial heterogeneity. In advanced NSCLC, metabolic parameters tumoural maximum standardised uptake value (SUVmax) and total lesion glycolysis (TLG) of 18F-FDG-PET/CT have been shown to correlate with PD-L1 expression. However, advanced status itself has been associated with high SUVmax and the relationship in early-stage disease has yet to be determined.
Methods:
This retrospective study included NSCLC patients who underwent primary resection at a UK cancer centre. PD-L1 tumour proportion score (TPS) was assessed using the 22C3 pharmDx DAKO assay. Pre-surgical 18F-FDG-PET/CT scans were assessed for metabolic parameters: SUVmax; SUVmean; SUVpeak; SULpeak (lean body mass corrected), metabolic tumour volume (MTV), TLG and SUV-based heterogeneity index (HISUV). 40 cases were assessed by 2 observers to determine interobserver reliability. To determine correlation between metabolic parameters and PD-L1 TPS, unpaired t-test, one-way ANOVA or Kruskall-Wallis tests were applied. Interobserver reliability was determined using intraclass correlation coefficient (ICC).
Results:
Patients (n=100) were grouped by primary tumour PD-L1 TPS of <1% (n=45), 1-49% (n=37) and ≥50% (n=18). There was no statistical difference between PD-L1 TPS groups for primary tumour SUVmax with mean SUVmax of 12.0 (95% CI 10.0-14.0) in PD-L1 <1% group, 14.0 (11.9-16.0) in PD-L1 1-49%, and 12.9 (10.2-15.7) in PD-L1 ≥50% (p=0.38). There was a non-significant trend in correlation with MTV with a mean MTV of 29.86 (19.2-40.6) in PD-L1 <1% group, 24.2 (14.3-34.2) in PD-L1 1-49%, and 15.5 (1.3-29.6) in PD-L1 ≥50% group (p=0.06). There was no significance between PD-L1 subgroups for SUVmean (p=0.48), SUVpeak (p=0.91), SULpeak (p=0.88), TLG (p=0.21) and HISUV (p=0.07). The ICCs between observers for all parameters were excellent (>0.9).
Conclusions:
There was no correlation between primary resected NSCLC 18F-FDG-PET/CT metabolic parameters and PD-L1 TPS. A trend toward significant correlation for MTV and HISUV warrants further investigation. Importantly, we determined that interobserver reliability was excellent.
| Original language | English |
|---|---|
| Pages | S931-S938 |
| DOIs | |
| Publication status | Published - 2021 |
