Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Introduction: Cervical lymph node involvement is one of the most important prognosticators in head and neck squamous cell carcinoma (SCC). It is associated with as much as a 50% reduction in overall survival. The presence of extra-nodal extension has also been identified as a poor prognosticator, and has been incorporated into the newest staging system for head and neck malignancies. Recently, the lymph node yield, defined as the number of lymph nodes retrieved per neck dissection, and the lymph node ratio, defined as the total number of lymph nodes divided by the number of positive lymph nodes, have emerged as important prognostic tools. These metrics are not only an idenx of disease burden, but also of surgical and pathological quality standards. The aim of the present study is to examine the impact of different lymph node yield cut-offs and the lymph node ratio on 10-year progression-free and overall survival.
Methods: A single center cohort study was carried out over a 10-year period. Patients met inclusion criteria if they underwent a laryngectomy or pharyngolaryngectomy for a squamous cell carcinoma of the larynx. Data collected included pathological factors, surgical characteristics, margin status, recurrence and overall survival.
Results: A total of 167 patients met inclusion criteria and were available for analysis. The mean age of the cohort was 63.7 years. The larynx was the most common primary site (84%), and salvage surgery was performed in 35% of cases. Close or involved margins were more likely with advanced laryngeal cancers and salvage surgery cases (p<0.001). The mean lymph node yield per neck dissection was 28 nodes, and the lymph node ratio was <0.05 and >=0.05 in 25% of cases (n=41 and 42 respectively). A lymph node yield of greater than 26 was significantly associated with an improved progression-free and overall survival (p<0.001, p<0.004 respectively). A lymph node ratio of >0.05 was associated with a worse progression-free and overall survival (p<0.001, p=0.006 respectively). The 10-year overall survival of the cohort was 42%, 55% for patients with a lymph node ratio of <0.05, and 23% for those with a ratio >=0.05 (p=0.001).
Discussion: Data from the present study demonstrates a strong associated between lymph node yield and the lymph node ratio in progression-free and overall survival in patients with advanced laryngeal and hypopharyngeal malignancies. This data supports incorporation of these metrics into staging and decision-making for this cohort of patients.