Increased risk of esophageal squamous cell carcinoma in patients with squamous dysplasia: a nationwide cohort study in the Netherlands.

Squamous dysplasia is the histological precursor of esophageal squamous cell carcinoma (ESCC). The optimal management for distinct squamous dysplasia grades remains unclear because the corresponding risk of developing ESCC is unknown. We aimed to assess the ESCC risk in patients with esophageal squamous dysplasia in a Western country. This nationwide cohort study included all patients with esophageal squamous dysplasia, diagnosed between 1991 and 2020 in the Dutch nationwide pathology databank (Palga). Squamous dysplasia was divided in mild-to-moderate dysplasia (mild, low-grade, and moderate dysplasia) and higher-grade dysplasia (high-grade dysplasia, severe dysplasia, carcinoma in situ). ESCC were identified in Palga and the Netherlands Cancer Registry. The primary endpoint was diagnosis of prevalent (≤6 months) and incident (>6 months after squamous dysplasia) ESCC. In total, 873 patients (55% male, aged 68 years SD ± 13.2) were diagnosed with esophageal squamous dysplasia, comprising mild-to-moderate dysplasia (n = 456), higher-grade dysplasia (n = 393), and dysplasia not otherwise specified (n = 24). ESCC was diagnosed in 77 (17%) patients with mild-to-moderate dysplasia (49 prevalent, 28 incident ESCC) and in 162 (41%) patients with higher-grade dysplasia (128 prevalent, 34 incident ESCC). After excluding prevalent ESCC, the annual risk of ESCC was 4.0% (95% CI: 2.7-5.7%) in patients with mild-to-moderate dysplasia and 8.5% (95% CI: 5.9-11.7%) in patients with higher-grade dysplasia. All patients with squamous dysplasia, including those with mild-to-moderate dysplasia, have a substantial risk of developing ESCC. Consequently, endoscopic surveillance of the esophageal mucosa or endoscopic resection of dysplasia should be considered for patients with mild-to-moderate dysplasia in Western countries. KEY MESSAGES What is already known on this topic? Squamous dysplasia is the histological precursor of ESCC and is divided in distinct grades, based on the proportion of the squamous epithelium with histopathological abnormalities. In Western countries, the optimal management for distinct squamous dysplasia grades remains unclear because the corresponding risk of developing ESCC is unknown. What this study adds The ESCC risk of patients with squamous dysplasia was increased for all patients with squamous dysplasia in a Western country; 2.1% for patients with mild dysplasia, 5.1% for low-grade dysplasia, and 5.2% for moderate dysplasia. Increasing grades of squamous dysplasia were associated with an increased ESCC risk. How this study might affect research, practice, or policy We recommend that endoscopic follow-up or treatment should be considered in all patients with esophageal squamous dysplasia in Western countries: 1) for patients with mild, low-grade, and moderate dysplasia, endoscopic surveillance with careful inspection with narrow band imaging or dye-based chromoendoscopy of the esophageal mucosa is indicated; and 2) for patients with high-grade dysplasia, severe dysplasia and carcinoma in situ adequate endoscopic staging and in case of suspected neoplasia endoscopic treatment should be performed.