Comparison of clinical and prognostic characteristics between superficial basaloid and conventional esophageal squamous carcinoma

Abstract Background and Aims: Superficial basaloid esophageal squamous cell carcinoma (SBSCC) is a rare subtype of early esophageal squamous cell carcinoma, and its characteristics have not been thoroughly investigated. This retrospective study aims to elucidate the clinicopathological features and outcomes of SBSCC resected via endoscopic submucosal dissection (ESD), with a comparison to superficial conventional esophageal squamous cell carcinoma (SCSCC). Methods: We identified patients with ESD-resected superficial esophageal squamous cell carcinoma at the Center of Gastrointestinal Endoscopy, Nanjing Drum Tower Hospital, from January 2014 to December 2019.Based on histopathologic findings, eligible cases were divided into SBSCC and SCSCC groups. The medical records, endoscopic and pathologic reports were reviewed for clinicopathologic and endoscopic information. All patients were routinely followed up at clinic and the outcomes were tabulated and statistically compared between the two groups. Results: Among 477 patients, 31 (6.5%) had SBSCC and 446 (93.5%) had SCSCC. The SBSCC group had a significantly higher proportion of male patients (P = 0.027), but there was no significant difference in age. Both groups showed similar rates of smoking, alcohol abuse, family cancer history, tumor size, location, en bloc resection, and ESD-related complications. However, complete and curative resection rates were significantly lower in the SBSCC group (74.2% and 58.1%) compared to the SCSCC group (91.5% and 75.6%) (P = 0.006 and P = 0.031). SBSCC also exhibited deeper invasion (P = 0.018) and more frequent vertical margin involvement (P = 0.010). The 5-year overall survival (OS) was comparable between the groups, but disease-free survival (DFS) was lower in the SBSCC group (90.3% vs. 97.8%; P = 0.046). Post-ESD surgery, chemoradiation therapy, and tumor recurrence were more common in the SBSCC group (P < 0.05). Multivariate analysis identified SBSCC as an independent risk factor for DFS (HR: 4.6; 95% CI: 1.990-10.650; P < 0.001), while lymphovascular invasion and complete resection were significant for OS. Conclusions: Our findings demonstrate that ESD is a safe and effective treatment for both SBSCC and SCSCC, with minimal complications and excellent outcomes. Compared to SCSCC, SBSCC is associated with significantly deeper invasion, lower rates of complete and curative resections, and lower disease-free survival.