Validation of sentinel lymph node biopsy in early stages of oropharyngeal cancer

Abstract

Background: Over the years the approach to cervical lymph node metastasis in oropharyngeal cancer has evolved to a more conservative form. The controversy arises in cases where it is not possible to detect cervical lymph node metastasis by means of clinical or imaging techniques. In these cases, elective neck dissection is traditionally recommended when the tumor size and subsite confers at least a 20% risk of lymphatic spread. This implies that a high percentage is submitted to a surgical procedure without need. Therefore, elective neck dissection is the current treatment and gold standard for neck staging. The sentinel lymph node biopsy is a promising technique that its application in clinical practice could imply the saving of an unnecessary surgical intervention. In the same way that it could play an important role in lymphatic staging as well as in prognosis, since lymphatic involvement is the main risk factor for decreased survival.

Obejective: The main objective is, on one hand, to determine the sensitivity, specificity and negative predictive value for sentinel lymph node biopsy validation and, on the other hand, to determine the recurrences and survival in the same group of patients in order to reinforce the validity of the sentinel lymph node.

Methods: A cross-sectional study will be conducted to establish the diagnostic test validation. A sample of 32 subjects selected in a consecutive non-probability manner will be analyzed. Once the lymphatic staging has been performed, the sample will be included in a secondary study. A longitudinal study will be carried out dividing the sample between two groups depending on the lymph node involvement. These two groups will be followed to evaluate local and regional recurrences at 2 years, as well as survival at 5 years. We will use Cox regression for the multivariate analysis