Esophageal Small Cell Carcinoma: From Bench Discoveries to Bedside Therapeutics

Small cell carcinoma of the esophagus (SCCE) is both rare and aggressive. Lacking its own guidelines, it has historically been managed with treatment models borrowed from small cell lung cancer (SCLC). However, advances in multi-omics and immunology are beginning to uncover distinct molecular and immune features in SCCE. These include frequent alterations in NOTCH1 and PTEN, ASCL1 and NEUROD1 transcriptional programs, and a highly adaptive immunosuppressive tumor microenvironment. Together, they point to unique biological traits that may be targetable. Clinically, conventional chemotherapy, radiotherapy, and surgery are being reassessed, with neoadjuvant therapy showing increasing value. Mechanism-driven strategies such as anti-angiogenic and DLL3-targeted therapies are under active exploration. At the same time, emerging biomarkers and multimodal predictive models are offering new tools for risk stratification and personalized management. Yet pathology adds further challenges: boundaries between SCCE, squamous cell or adenocarcinomas with neuroendocrine differentiation, and mixed or collision tumors remain blurred, creating diagnostic and therapeutic uncertainty. These challenges highlight an important shift-SCCE is no longer a clinical "black box" but rather a frontier that demands resolution through a translational lens. By realigning fragmented basic research with clinical evidence, this review not only presents a comprehensive picture of SCCE but also aims to provide clear therapeutic direction for this malignancy.