2256 - Efficacy of Combined Chemoradiotherapy and Immunotherapy vs. Chemoradiotherapy Alone in Patients Aged 70 Years and Older With Locally Advanced or Oligometastatic Esophageal Cancer

Purpose/Objective(s): The hypothesis is that the addition of immunotherapy to chemoradiotherapy (CRT) is associated with improved survival outcomes compared to CRT alone in elderly patients with esophageal squamous cell carcinoma (ESCC). The primary objective was to compare progression-free survival (PFS) and overall survival (OS) between the two treatment strategies.

Materials/Methods: This retrospective cohort study, approved by the Institutional Review Board of Shandong Cancer Hospital and Institute (Approval No. 202511024), enrolled elderly patients (aged =70 years) with thoracic ESCC that was either locally advanced unresectable or oligometastatic (involving only non-regional lymph nodes). Patients in the CRT group received radiotherapy (=50 Gy in 1.8/2.0 Gy per fraction) combined with concurrent or sequential chemotherapy (paclitaxel or fluoropyrimidine ± platinum, administered intravenously or orally). Patients in the chemoradiotherapy plus immunotherapy (CRIT) group received the same CRT backbone with the addition of immunotherapeutic agents at various time points. The primary endpoints were PFS and OS. Secondary endpoints included objective response rate (ORR), disease control rate (DCR), safety profile, and subgroup analyses based on clinical characteristics.

Results: A total of 160 patients were enrolled (CRIT: 57; CRT: 103). No significant difference in OS was observed between the two groups (median OS: 26.4 vs 30.1 months; HR = 1.044, 95%CI: 0.67–1.62, p = 0.845). However, a statistically significant improvement in PFS was observed in the CRIT group (median PFS: 26.4 vs 14.8 months; HR = 0.625, 95%CI: 0.40–0.98, p = 0.037). Multivariate Cox analysis identified no independent predictors for either PFS or OS. Subgroup analyses suggested that patients with a smoking index of <200 pack-years, never/light alcohol consumption, normal BMI (=24.9 kg/m²), or a radiation dose exceeding 54 Gy may derive greater benefit from combination therapy. Grade =3 adverse events were slightly higher in the CRIT group (41.4% vs 33.0%) but were considered clinically manageable.

Conclusion: First-line chemoradiotherapy plus immunotherapy demonstrated a significant PFS benefit compared to CRT alone in elderly patients with esophageal cancer, though no OS difference was observed. The combination regimen had an acceptable toxicity profile. These findings warrant validation in prospective randomized trials.