The role of PMI in evaluating the efficacy of PD-1 inhibitors and prognosis of patients treated for advanced esophageal squamous cell carcinoma

Abstract

Abstract Background Skeletal muscle loss is an indicator of poor prognosis for various malignant tumours, including ESCC. We assessed whether the baseline psoas muscle mass index (PMI) could predict the response of ESCC to sintilimab treatment, with progression-free survival (PFS) and objective response rate (ORR) as the outcome measures.Methods A retrospective analysis of 51 patients with advanced ESCC who received immune checkpoint inhibitor (ICI) therapy. Efficacy was evaluated using immune response evaluation criteria in solid tumour (iRECIST), and the Kaplan‒Meier method was used to calculate the PFS and overall survival (OS). Univariate and multivariate Cox proportional hazards regression models were used to analyse prognostic factors.Results A total of 51 patients were included (1 immune complete response (iCR), 14 immune partial response (iPR), 28 immune stable disease (iSD), and 8 immune progressive disease (iPD). The overall ORR was 29.4%, and the disease control rate (DCR) was 84.3%. The ORR in the low PMI group was significantly lower than that in the high PMI group (21% vs. 53.8%). The median PFS was significantly prolonged in the high PMI group compared with that in the low PMI group (11.0 months vs. 6.0 months, HR = 2.796, 95% CI 1.262–6.198, p = 0.011). The median PFS was significantly prolonged in the high prognostic nutritional index (PNI) group compared with that in the low PNI group (10.0 months vs. 6.0 months, HR = 1.974, 95% CI 1.014–3.842, p = 0.045). The univariate analysis results indicated that low PMI and low PNI were poor prognostic factors for PFS (p < 0.05), and the multivariate Cox analysis results indicated that low PMI (HR = 2.588, 95% CI,1.163–5.758, p = 0.020) was an independent risk factor for PFS after immunotherapy for advanced ESCC.Conclusions The PMI can help predict the response to immunotherapy in patients with advanced ESCC.