Abstract
INTRODUCTION: Esophageal squamous cell carcinoma (ESCC) remains a major cause of cancer-related mortality in Asia. Pembrolizumab in combination with chemotherapy has become a standard first-line option based on phase III trial data, but real-world evidence from Vietnam is lacking. This study examined the clinical characteristics, disease course, and treatment-related toxicities of Vietnamese patients with stage IV ESCC receiving this regimen. METHODS: We conducted a single-center, single-arm, retrospective analysis of 53 patients with stage IV ESCC treated with pembrolizumab plus platinum- and fluoropyrimidine-based chemotherapy. Information on demographics, clinical presentation, pathology, biomarker status, treatment regimens, patterns of progression or recurrence, and adverse events (AEs) was collected from electronic health records. RESULTS: The mean age was 59 years, with nearly all patients being male. Most presented with advanced T3/N2 disease and dysphagia at diagnosis. PD-L1 status was unavailable in about one-third of cases. Common chemotherapy backbones were CF (50.9%) and XELOX/SOX (24.5%). Progression or recurrence was documented in 24.5% of patients, and 20.8% occurred within six months. Lymph nodes were the most frequent site of progression, followed by local and distant recurrence. Hematologic toxicities were common, including neutropenia (43.4% all grades, 13.2% grade ≥3) and anemia (50.9% all grades). Nausea (20.8%) and diarrhea (5.7%) were the main gastrointestinal toxicities. Immune-related events included hypothyroidism (3.8%) and pneumonitis (3.8%). CONCLUSIONS: In this Vietnamese cohort, pembrolizumab plus chemotherapy showed a manageable safety profile and recurrence patterns consistent with those reported internationally. These findings add region-specific real-world evidence and underline the importance of broader multi-center studies with longer follow-up to inform practice in advanced ESCC.