A retrospective investigation of minor risk factors as prognostic predictors and treatment indications in oral squamous cell carcinoma

Background/purpose: The clinical significance of minor risk factors remins uncertain in oral squamous cell carcinoma (OSCC) patients. The purpose of this study was to investigate the clinical impact of minor risk factors in OSCC patients. Materials and methods: The cases of OSCC patients that underwent surgery were retrospectively analyzed. Patients with major risk factors for recurrence, such as positive surgical margins or extracapsular spread, were excluded. The impact of possible minor risk factors on treatment outcomes was analyzed. One hundred and seventy-five patients with primary OSCC that underwent surgery were included in this study. Results: The 5-year overall survival (OS), cancer-specific survival (CSS), and relapse-free survival (RFS) rates were 81.2%, 91.0%, and 72.4%, respectively. In multivariate analyses, RFS exhibited a significant association with the pattern of invasion (grade 4 vs. grades 1-3: hazard ratio: 3.096, 95% confidence interval: 1.367-6.884, p < 0.01), OS exhibited a tendency towards associations with the pattern of invasion and perineural invasion, and CSS displayed a tendency towards an association with perineural invasion. The prognosis of the patients with >= 2 minor risk factors was significantly worse than that of the patients with 0 or 1 minor risk factor(s) (OS: 91.6% vs. 64.5%, respectively, p < 0.01; CSS: 98.9% vs. 78.9%, respectively, p < 0.001; and RFS: 81.2% vs. 58.5%, respectively p < 0.05). Conclusion: Grade 4 invasion and perineural invasion might be significant minor risk factors in OSCC patients. The presence of >= 2 minor risk factors might be a predictor of a poor prognosis in OSCC patients. (C) 2020 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.