Prognostic significance of keratinization in squamous cell cancer of uterine cervix: a population based study

To determine the influence of keratinization on prognosis in squamous cell cancer (SCC) of the uterine cervix. Patients with keratinized squamous cell carcinoma (KSCC) and non-keratinized squamous cell carcinoma (NKSCC) of the cervix were identified from the Limited Use SEER database from 1988 to 2004. A subgroup of patients who did not have radiation or surgery formed the basis to study the natural history of the disease. Data were analyzed using Pearson Chi-square, Student's T tests. Kaplan-Meier and Cox Regression Proportional Hazards survival analysis was conducted in SPSS and SEER-Stat software. The KSCC group had 3,102 and the NKSCC had 3,751 patients with mean age being 51 and 49 years, respectively (P = 0.001). In general, patients with KSCC were more likely to have advanced stage (FIGO III and IV) disease while patients with NKSCC were more likely to have poorly differentiated neoplasms (P < 0.001). The prevalence of lymph node metastasis remained similar in both histology types (P > 0.05). Overall, the 5-year survival in KSCC was 63.4% as compared to 65.3% in the NKSCC group (P = 0.04). Patients treated by surgery had no difference in survival; however, patients treated by radiation had a median survival in KSCC of 33 months (n = 928, 95% CI 27.7-38.3) as compared to 38 months (n = 1,140, 95% CI 32.1-43.8) in NKSCC (P = 0.03). A total of 165 KSCC and 147 NKSCC patients did not receive treatment. Within this subgroup, the median survival was 10 months (95% CI 5.93-14.07) as compared to 28 months (95% CI 17.9-38.0; P = 0.001) respectively for the two cohorts. In multivariate analysis stage, treatment status, nodal metastasis and keratinization were independent predictors of survival (P < 0.05). This is the largest study reporting on the prognostic importance of keratinization in SCC. KSCC may be less radiosensitive and associated with shorter overall survival. Also, in the natural history of the SCC, keratinization signifies striking reduction in survival.