Objectives: This study evaluated associations between the histological differentiation of oral squamous cell carcinoma and additional clinicopathological manifestations, adverse events after treatment, and the outcomes of patients in a region prevalent for betel quid chewing.
Study design: Case series with chart review.
Setting: Tertiary referral center.
Subjects and methods: A total of 150 patients with primary oral squamous cell carcinomas who underwent surgery with or without adjuvant therapy were enrolled.
Results: Well, moderate, and poorly differentiated oral squamous cell carcinomas were reported in 54 (36%), 84 (56%), and 12 (8%) patients, respectively. There were no significant differences among different histological differentiations in age, sex, tumor, node, metastasis stage, bone invasion, depth of invasion, and history of carcinogen exposure. However, we found significant associations between tumor histological differentiation and nodal metastasis (P < 0.0001), extracapsular spread (P = 0.002), and perineural invasion (P < 0.0001). In the analysis of adverse events for survival during patient follow-up, oral squamous cell carcinomas with poor differentiation had a higher probability of developing neck recurrence (P = 0.001) and distant metastasis (P = 0.019), but not local recurrence or a second primary cancer. For survival analysis, univariate analysis showed that patient age, tumor stage, extracapsular spread, presence of perineural invasion, and tumor differentiation were significant factors. Multivariate analysis further demonstrated that poor differentiation (P = 0.007) was still a statistically significant factor.
Conclusion: The current study demonstrates that poorer tumor histological classifications of oral squamous cell carcinoma are significantly associated with positive nodal status, extracapsular spread, perineural invasion of primary tumors, and the probability of developing neck recurrence and distant metastasis after treatment.