Prognostic implication of erector spinae muscles in non-small-cell lung cancer patients treated with immuno-oncology combinatorial chemotherapy

Background: The quantity of skeletal muscles has recently been reported to have prognostic value in patients with non-small-cell lung cancer (NSCLC) treated with second-line immunotherapy. However, the prognostic role of skeletal muscle assessment in NSCLC patients undergoing first-line immuno-oncology (IO) combinatorial treatment (IO-chemotherapy) has not been elucidated.

Methods: We retrospectively reviewed 36 patients with NSCLC undergoing first-line IO-chemotherapy between April 2018 and June 2021 in our hospital. The cross-sectional area of the erector spinae muscle (ESM_CSA ) was evaluated by manual tracing on computed tomography scans at the level of the 12th thoracic vertebra before initiating IO-chemotherapy. To minimize deviation due to physique, the ESM_CSA was adjusted by body surface area (BSA) (ESM_CSA to BSA ratio: ESM_CSA /BSA). A survival time analysis was performed using the Kaplan-Meier method and log-rank test. A multivariate analysis with Cox proportional hazards model was conducted to investigate the prognostic value of the ESM_CSA /BSA and inflammatory and nutritional indices.

Results: The median progression-free survival (PFS) and overall survival (OS) were 6.5 and 16.6 months, respectively. Intergroup comparison by the log-rank test revealed that there was no significant difference in the median PFS, but the median OS was significantly long in the high ESM_CSA /BSA (>19 cm^2/ m² ) (high ESM_CSA /BSA group, p = 0.0373). The multivariate analysis showed that ESM_CSA /BSA was an independent prognostic factor for OS (hazard ratio 0.79, p = 0.044).

Conclusions: The results of this study indicate that the pretreatment ESM_CSA /BSA may be a potential prognostic factor in NSCLC patients receiving first-line IO-chemotherapy.