Background: In the treatment of oral cavity squamous cell carcinoma (OCSCC), surgical quality measures which are expected to affect outcomes, including the achievement of a clear margin, are surgeon-dependent but might not be invariably associated with hospital volume. Our objective was to explore surgical margin variations and survival differences of OCSCC between two highest-volume hospitals in Taiwan.
Materials and methods: A total of 2009 and 1019 patients with OCSCC who were treated at the two highest-volume Taiwanese hospitals (termed Hospital 1 and Hospital 2, respectively) were included. We examined how a pathological margin <5 mm impacted patient outcomes before and after propensity score (PS) matching.
Results: The prevalence of margins <5 mm was markedly lower in Hospital 1 than in Hospital 2 (34.5%/65.2%, p<0.0001). Compared with Hospital 2, tumor severity was higher in Hospital 1. On univariable analysis, being treated in Hospital 2 (versus Hospital 1; hazard ratio [HR] for 5-year disease-specific survival [DSS] = 1.34, p=0.0002; HR for 5-year overall survival [OS] = 1.17, p=0.0271) and margins <5 mm (versus ≥5 mm; HR for 5-year DSS = 1.63, p<0.0001; HR for 5-year OS = 1.48, p<0.0001) were identified as adverse factors. The associations of treatment in Hospital 2 and margins <5 mm with less favorable outcomes remained significant after adjustment for potential confounders in multivariable analyses, as well as in the PS-matched cohort. The 5-year survival differences between patients operated in Hospital 1 and Hospital 2 were even more pronounced in the PS-matched cohort (before PS matching: DSS, 79%/74%, p=0.0002; OS, 71%/68%, p=0.0269; after PS matching: DSS, 84%/72%, p<0.0001; OS, 75%/66%, p<0.0001). In the entire cohort, the rate of adjuvant therapy was found to be lower in patients with margins ≥5 mm than in those with margins <5 mm (42.7%/57.0%, p<0.0001).
Conclusions: Within the two highest-volume hospitals in Taiwan, patients with OCSCC with a clear margin status (≥5 mm) achieved more favorable outcomes. These results have clinical implications and show how initiatives aimed at improving the margin quality can translate in better outcomes. A clear margin status can reduce the need for adjuvant therapy, ultimately improving quality of life.
Keywords: cancer registry; hospital volumes; oral cavity squamous cell carcinoma; propensity score matching; survival outcomes; volume-outcome.
Copyright © 2022 Liao, Lee, Lee, Ng, Liu, Chien, Lin, Wang, Terng, Hua, Chen, Chen, Tsai, Kang, Tsai, Chu, Lin, Fan, Wang, Hsieh, Yeh, Lin, Tsao, Yen, Cheng, Fang, Huang, Lee, Fang, Wang, Lin, Hsin and Wen.