(A565) Incidence and Predictors of Occult Lymph Node Metastasis in Clinically N0 Head and Neck Cancer

Introduction: To determine the incidence of occult lymph node metastasis detected in patients with clinically N0 head and neck cancer undergoing elective neck dissection.

Methods: A total of 50 patients of all age groups and both sexes were selected, all having biopsy-proven head and neck cancer with a clinically N0 neck. All patients underwent elective neck dissection along with surgical excision of the primary tumor. A total of 50 neck dissections were performed. Nodes in each neck dissection specimen were examined microscopically by a pathologist. The histopathology results of the patients were documented, and the proportion of patients with occult lymph node metastasis was calculated. Additionally, the primary tumors with a higher probability of occult lymph node metastasis were determined.

Results: Out of 50 patients (39 males, 11 females; mean age 46, range 22-72), the most common primary tumor sites were buccal mucosa (40%) and tongue (32%), followed by lower alveolus (14%), larynx (12%), and lip (2%). Occult nodal metastasis was detected in 12 patients (24%). Occult metastasis rates by primary site were as follows: buccal mucosa (25%), lower alveolus (28.57%), tongue (25%), and larynx (16.66%). All metastases were found on the ipsilateral side of the neck. Overall, 24% of all clinically N0 primaries had occult nodal metastases detected on histopathology, with 12 patients (24%) upstaged from clinically N0 to histopathologically N+.The negative predictive value of clinical examination was 76%. Out of the 50 patients, 39 had no complications, while 11 had some complications. During one year of follow-up, four patients experienced recurrence (3ipsilateral,1contralateral).

Conclusions: Occult lymph node metastasis is an important issue that should be considered in cases of head and neck cancers. The location of the primary tumor is a significant influencing factor regarding this issue. Both early-stage and advanced local disease carry a risk of occult metastasis. Elective neck dissection is recommended for the management of clinically N0 head and neck cancer.