Recurrence and Survival Factors After Treating External Auditory Canal SCC: A Multicenter Cohort and Meta-analysis

Introduction: External auditory canal squamous cell carcinoma (EAC SCC) is a rare but aggressive malignancy. This study aimed to analyze recurrence and survival factors in EAC SCC through a multicenter cohort and meta-analysis.

Methods: Data from EAC SCC patients (2007–2022) in the Chang Gung Research Database were retrospectively reviewed. Cox regression models assessed overall survival (OS) and time to progression (TTP). Kaplan-Meier analysis and stepwise model selection identified significant predictors. Additionally, a systematic search of PubMed, Embase, and Cochrane (up to December 31, 2024) was conducted. Random-effects models were applied for meta-analysis, with meta-regression and sensitivity analysis exploring heterogeneity.

Results: A total of 87 patients were included. The median age was 66 years (IQR: 56–74), with a male predominance (64.4%) and advanced stages (T3&4: 57.5%). Crude hazard ratios (HRs) showed significant poor outcomes for advanced cancer status, including T4 tumors (OS: HR 4.98, p=0.003; TTP: HR 5.78, p=0.020), positive nodal status (OS: HR 3.59, p=0.002; TTP: HR 3.24, p=0.018), and primary (C)RT or (C)RT followed by salvage surgery (OS: HR 3.05, p=0.008; TTP: HR 4.04, p=0.030). Multivariable analysis confirmed these factors with higher hazards for OS and TTP, though without statistical significance. Meta-analysis revealed that (C)RT as the primary treatment was associated with poorer oncologic outcomes (OS: HR 2.81, p=0.003; TTP: HR 3.55, p=0.011).

Conclusions: Surgery appears to be the optimal primary treatment strategy for improving OS and TTP in EAC SCC. These findings highlight the need for surgical prioritization in clinical practice and underscore the importance of prospective validation.