Postoperative adjuvant PD-1 immunotherapy survival and body-mass-index dynamics in esophageal cancer: A real-world retrospective study.

Background: Esophageal cancer (EC), primarily esophageal squamous cell carcinoma in China, has a poor prognosis with a 5-year survival rate of approximately 25% after surgery alone. Neoadjuvant chemoradiotherapy combined with surgery is the standard treatment for locally advanced EC, with a 47% 5-year survival rate, although adverse events are common. Immunotherapy, particularly PD-1 inhibitors, has shown promise in treating advanced EC, and neoadjuvant chemotherapy with immunotherapy is effective. However, the efficacy of postoperative immunotherapy remains unclear, with studies like Checkmate577 showing promising results but limited applicability to surgery-only patients, highlighting the need for further research.

Aim: To evaluate the efficacy, prognostic factors, and safety of adjuvant immunotherapy with anti-PD-1 inhibitors following radical surgery for EC.

Methods: A retrospective analysis was conducted on EC patients who received adjuvant immunotherapy after radical treatment at the 900^th Hospital of the China Joint Logistics Force between January 2018 and October 2024. Demographic, treatment and laboratory data were collected. Progression-free survival (PFS) was assessed using the Kaplan-Meier method, and independent prognostic factors were identified using Cox regression. Optimal cutoff values for continuous variables, including body mass index (BMI) difference and neutrophil-to-lymphocyte ratio (NLR), were determined using the maxstat package in R.

Results: A total of 44 patients were included, with a 2-year PFS rate of 68.6% [95% confidence interval (CI): 53%-88.7%]. Univariate analysis identified several factors significantly associated with prognosis, including the interval between surgery and immunotherapy, BMI difference between before surgery and first immunotherapy, presurgical lymphocyte count, and presurgical NLR. Multivariable Cox regression revealed that a BMI difference < 3.86 was an independent protective factor for PFS (hazard ratio: 0.42, 95%CI: 0.21-0.85, P < 0.05). At the last follow-up, the median PFS for patients with BMI < 3.86 had not been reached, compared to 8.83 months for those with BMI > 3.86. The 1-year PFS for patients receiving postoperative chemotherapy combined with immunotherapy was 88.5%, suggesting superior efficacy over chemotherapy alone.

Conclusion: Adjuvant immunotherapy for EC shows good efficacy and safety. A BMI difference < 3.86 is a protective factor for PFS, highlighting the importance of monitoring nutrition and inflammation for personalized treatment.