Background: The prognostic nutritional index is a surrogate marker combining baseline albumin and neutrophil count and has been predictive of both progression free survival (PFS) and overall survival in metastatic non-small cell lung cancer (NSCLC). This study investigates the role of PNI as a surrogate for the survival outcomes for patients with unresectable stage III NSCLC treated with chemoradiation followed by durvalumab.
Methods: This retrospective observational study was conducted across six sites in Sydney, Australia. It included all patients diagnosed with unresectable stage III NSCLC treated with chemoradiation and who received at least one cycle of durvalumab between January 2018 and September 2021. The PNI was calculated as 10 × serum albumin value (g/dL) + 0.005 × total lymphocyte count (per mm3) in peripheral blood.
Results: 144 patients were included in the analysis. The mean age was 66 years. The median PNI was 13.6 in the total cohort. Patients were stratified into either PNI < 13.5 (PNI-Low) or PNI >= 13.5 (PNI-High). At a median follow-up of 21.8 months from durvalumab initiation, median progression free survival (PFS) in PNI-High group was not reached versus 19.9 months in the PNI-Low group (HR 0.58, 95% CI 0.34 – 0.99, p=0.049). There was no statistically significant difference in overall survival between the two groups. Multivariate analysis demonstrated that PNI remained independently prognostic for PFS when stratified with age or presence of significant cardiac or respiratory comorbidities (p=0.048).
Conclusions: Our data adds to the growing evidence that suggests that combination nutritional – haematological surrogates are predictive in survival outcomes for patients with NSCLC. This is the first Australian data to report the possibility of PNI as a surrogate marker for PFS in the stage III NSCLC setting. Further research regarding its predictive utility in larger cohorts is required for incorporation into predictive survival models.