Brush Cytology: A Simple Diagnostic Tool in Oral/Oropharyngeal Lesions with P16 Immunocytochemistry

Background: Oral/Oropharyngeal cancers, particularly oropharyngeal squamous cell carcinoma (OPSCC) comprise about 85% of the head and neck cancers. At present, these cancers constitute the sixth leading cause of cancer related deaths around the globe. With the advent of HPV as a causative agent of oral/oropharyngeal cancers associated with good prognosis, the search for adjunctive tests for diagnosis of these lesions have received a great deal of interest.

Aims and Objectives: This study was conducted to study the efficacy of brush cytology in the diagnosis of potentially malignant and malignant oral/ oropharyngeal lesions in adjunct with p16INK4a Immunocytochemistry.

Materials and Methods: This is a prospective study performed in a tertiary care hospital in 50 patients attending the outpatient department of Otorhinolaryngology with suspected oral/oropharyngeal lesions from Jun 2018-January 2020.In all the selected cases, brush cytology material was obtained from the suspicious lesions and subjected to cytological examination. Histopathological examination of the punch biopsy specimens of respective lesions of all the selected cases was done. Cytopathology and histopathology findings were compared. Sensitivity, specificity, positive and negative predictive values were calculated Immunocytochemical staining for p16 was performed. Comparison of clinicopathological parameters with the p16 status was done.

Results: In our series of 50 patients, 35(70%) were males and 15(30%) were females. The age range was 31-90 years with a mean age of 51 years. Using the brush cytology technique, the cases detected were 27(54%) of squamous cell carcinomas, 13(26%) of epithelial dysplasia and 4(8%) of verrucous carcinoma, 4 (8%) leukoplakia, 2 cases were inconclusive. The sensitivity of brush cytology method was found to be 94% and the specificity was 94%, false positive rate was 6% and false negative rate was 6% witha diagnostic accuracy of 94%. Considering p16 as the surrogate marker of HPV infection, it was found to be positive in 28(56%) of cases by ICC. Statistically significant relation was found between the detection of p16 expression by ICC and the cytological diagnosis (p< 0.05).

Conclusion: Brush cytology provides a reliable diagnoses that is consistent with the final histopathological diagnosis. It is an efficacious technique that offers a less invasive and cost effective adjunctive assessment and is also appropriate for monitoring of patients with premalignant/malignant oral lesions in the long run.