Screening for Esophageal Squamous Cell Carcinoma: A Review

Esophageal cancer is amongst the most common types of cancer in Asia. It is a deadly disease where incidence almost parallels mortality. It is of 2 major subtypes, adenocarcinoma being more common in the global north and squamous cell carcinoma being more common in the global south. China, Japan, India, Iran, and other Asian countries contribute to roughly 80% of the global disease burden. Fortunately, esophageal squamous cell cancers (ESCC) are also amenable for screening. Natural history studies have shown that severe dysplasia carries the highest risk of progression to ESCC. Early detection has shown to be extremely beneficial, with cure rates above 90% for precursor lesions and early-stage esophageal cancer. There are various modalities available for screening—Chinese balloon cytology is a low cost technique that can be applied for mass screening but has only moderate sensitivity (39%-62%). Recent studies have demonstrated that using methylated DNA markers and applying artificial intelligence technology can significantly improve the yield of cytology. Lugol’s chromo-endoscopy has been demonstrated to have good sensitivity and specificity (>85%), but is an invasive technique and requires operator expertise. Other image enhancing techniques such as narrow-band imaging, autofluorescence, endocytoscopy and micro-endoscopy are promising, but currently not cost effective for mass screening. There are 3 large randomized trials underway in China, initial published results have demonstrated a detection rate between 0.7% to 1.2% for ESCC and 4% to 6% for pre cursor lesions. These trials, with some of them involving >100 000 patients have demonstrated the feasibility of endoscopic screening, but long term results are awaited.