Determination of lymph node micrometastases in patients with supraglottic carcinoma

Conclusions. The frequency of loss of heterozygosity (LOH) at D9S 171 microsatellite locus on 9p21 may serve as an available method to evaluate occult micrometastases in laryngeal squamous cell carcinoma. High frequency of LOH was associated with a decreased probability of survival time. Objective. To explore an available and sensitive method to detect cervical lymph node micrometastases in patients with laryngeal squamous cell carcinoma, the frequency of LOH at D9S171 microsatellite locus on 9p21 was studied. Patients and methods. Twenty samples from supraglottic cancer and 182 lymph nodes from neck dissections were examined by LOH comparing immunohistochemical (IHC) staining using cytokeratin 19 (CK19), and hematoxylin and eosin (H&E) staining. The frequency of lymph node metastasis and the clinical relevance were analysed. Results. The frequency of LOH was 37.4% of lymph nodes and all of the primary tumors. Occult micrometastases were present in 9 of 20 cases; 23.6% of lymph nodes were positive for CK19 by IHC; 16.5% of lymph nodes were positive by H&E. There was a highly significant difference among the three methods. The highest rate of positive lymph nodes was at level II of the neck. There was a highly significant difference between overall survival time and lymph node metastasis with LOH and CK19 analysis.