Prognostic Significance of the T12-SMI Before and After Neoadjuvant Chemoimmunotherapy for Esophageal Squamous Cell Carcinoma.

Abstract

This study evaluated the prognostic value of the 12th thoracic vertebra skeletal muscle mass index (T12-SMI) before and after neoadjuvant chemoimmunotherapy (NACI) in patients with esophageal squamous cell carcinoma (ESCC). We retrospectively analyzed 211 patients with ESCC who underwent NACI followed by esophagectomy between 2020 and 2022. According to their SMI at T12, the patients were divided into a muscle attenuation group (MAG) and a normal group (NG) before or after NACI. The perioperative outcomes and survival data were compared between the two groups. The pathological complete response (pCR) rates and major pathological response rates were comparable between the MAG and NG before and after NACI (all P > 0.05). The postoperative complication rates and 90-day mortality rates were also comparable (all P > 0.05). However, compared with the NG, the MAG had significantly worse overall survival and disease-free survival, both before and after NACI (all P < 0.05). Multivariate analyses confirmed that muscle attenuation post-NACI was an independent prognostic factor for overall survival (hazard ratio 2.977; 95% confidence interval 1.733-5.113; P < 0.001) and disease-free survival (hazard ratio 2.355; 95% confidence interval 1.339-4.142; P = 0.003). Post-NACI, the MAG had higher overall recurrence rates (41.7% vs. 21.1%, P = 0.009), particularly for distant metastases (22.2% vs. 9.1%, P = 0.024). Sarcopenia at the T12 level after NACI is an independent predictor of poor survival for patients with ESCC and is associated with increased postoperative recurrence risk, especially for distant metastases.