Invasive front grading: reliability and usefulness in the management of oral squamous cell carcinoma.

Background: The value of histological grading was examined with emphasis on reliability of assessment in 102 cases of intraoral squamous cell carcinoma from Northern Ireland with known outcome. Methods: Two pathologists independently graded the invasive tumour front blinded to the stage and outcome. Results: Intraobserver agreement was acceptable but interobserver agreement was not satisfactory. The degree of keratinisation was assessed most consistently while nuclear polymorphism was the least reliable feature. Multivariate survival analysis showed that the total grading score was associated with overall survival while the pattern of tumour invasion was the most valuable feature in estimating regional lymph node involvement. The number of positive lymph nodes was strongly associated with regional relapse, while the treatment modality and status of the surgical margins correlated with local relapse. Conclusions: Grading of selected features in OSCC is reliable and can facilitate treatment planning.