Incidence of metastasis to level V lymph nodes in clinically positive necks among Sri Lankan patients with oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) remains the most common cancer among males in Sri Lanka. Metastasis to neck is a crucial prognostic factor. A modified radical/radical neck dissection including levels I -V, was performed in patients with OSCC who had a clinically positive neck (cN+). Currently, evidence suggests that sparing level V in a cN+ may be justified due to less chance of metastasis in early stages of the disease. To the best of our knowledge, the incidence of metastasis to level V in patients with cN+s has not been previously investigated in a Sri Lankan context. We aimed to determine level V lymph node metastasis and related clinicopathological indicators in cN+s in patients with OSCC. A multicentre retrospective study investigated postoperative biopsy reports of 187 patients for five years. OSCC patients with cN+s who underwent neck dissections of levels I-V were included. Only 6.4% of patients had histopathologically positive level V lymph nodes. A total of 127 lymph nodes were harvested from level V of those who showed level V positivity and out of them 68 were positive with a third of cases showing extranodal extension (ENE). The buccal mucosa (n=4) and lateral aspect of the anterior two thirds of the tongue (n=4) were the common primary sites for level V metastasis. In patients who showed positivity in levels III and IV, a considerably higher probability of level V nodes being positive was seen, which was statistically significant (p = 0.0001). We have concluded that the routine performance of a modified radical/radical neck dissection for cN+s should be stopped, as the incidence of Level V positivity is significantly low. Assessing the cN+ for N stage, status of levels III and IV, pattern of invasion, differentiation, and the site may be used instead as predictors for level V positivity.