Occult Metastasis: Incidence, Pattern, and Impact on Survival in Patients with Oral Cancer, pN0 vs pN1 in a Cohort of cN0. A Prospective Cohort Study.

Squamous cell carcinoma of the oral cavity is the most common malignancy of head and neck cancer in India. With nodal dissemination, there is a significant decrease in survival. This study is aimed at studying the impact of occult metastasis on an estimated overall survival in clinically N0 patients post neck dissection. In a prospective study with 110 patients with squamous cell carcinoma of the oral cavity, clinically N0 with all T stages were included in the study. operated on for both primary and neck followed up for a median of 5 years after completion of definitive treatment. The impact of surgery on patients with occult metastasis was questionable in our study with a difference in estimated overall survival of around 11 months, which was not significant statistically. Subset analysis had shown the correlation of overall survival with a grade of tumor, T stage and depth of invasion which was statistically insignificant. Correlation of occult metastasis with the depth of invasion, T stage was statistically significant. we conclude that even after addressing the neck in clinically N0 patients with oral cancer, there is a difference in the overall survival of the patients with occult metastasis which might not be statistically significant with a p-value of 0.68. We conclude that with neck dissection in patients with occult metastasis, improved survival might not be comparable to pathological N0. Level of Evidence: LEVEL -2.