Neoadjuvant chemoimmunotherapy for small cell carcinoma of the esophagus: Clinical efficacy and biomarker exploration

Small cell carcinoma of the esophagus (SCCE) is a rare and highly malignant type of esophageal cancer with no standard treatment, facing challenges of resistance to conventional therapies. This study presents the cases of one extensive-stage and two limited-stage SCCE patients treated with chemoimmunotherapy. The two limited-stage patients underwent surgery post-treatment and experienced notable and enduring positive responses. This represents the first documented application of neoadjuvant chemoimmunotherapy in limited-stage SCCE patients. Additionally, comprehensive immunohistochemical analysis and whole exome sequencing were performed on the case patients. The findings revealed that infiltration of CD8⁺ T cells and PD-L1 expression in the SCCE tumor were key factors for favorable responses in SCCE patients receiving chemoimmunotherapy.