Degree of Keratinization Is an Independent Prognostic Factor in Oral Squamous Cell Carcinoma

Keratinization is a routinely reported histologic feature in head and neck cancer. In contrast to numerous clinicopathologic parameters, the prognostic value of keratinization in oral squamous cell carcinoma (OSCC) is rarely reported in the literature. The purpose of this study was to review the outcome of patients with OSCC with a special focus on the degree of keratinization.

In this retrospective cohort study, we evaluated the medical records at the Department of Oral and Maxillofacial Surgery, Jena University Hospital, and investigated the outcome of patients with OSCC with disease-free survival and disease-specific survival according to the degree of keratinization. This research also analyzed common clinical and histologic parameters such as age, gender, tumor site, T category, N category, resection margin, lymphovascular invasion, and extracapsular spread. Descriptive statistics were performed, and survival was calculated by the Kaplan-Meier method. Prognostic factors were analyzed by multivariate Cox analysis.

In the sample of 151 OSCC patients, with a median age of 57.5 years and a male-female ratio of 4.03:1, 119 had tumors with no or low keratinization (K0 to K2) and 32 had tumors with good or high keratinization (K3 or K4). More recurrences were seen in patients with OSCC with low keratinization (P = .0008). The 5-year disease-free survival rate was significantly decreased for OSCC with low keratinization (52.9%) compared with good or high keratinization (93.2%) (P = .0008). The 5-year disease-specific survival rate was reduced to 66.1% (P = .0136) for patients with OSCC with low keratinization. Multivariate analysis showed that extracapsular spread (P = .001) and keratinization (P = .002) are independent, significant prognostic factors for recurrence in OSCC.

Besides extracapsular spread, the degree of keratinization seems to be an important prognostic factor for recurrence and survival in OSCC. Our results indicate that the degree of keratinization should be considered in decisions regarding treatment and prognosis for OSCC.