Distribution of metastatic lymph nodes in oropharyngeal carcinoma and its implications for the elective treatment of the neck.

OBJECTIVES To analyze the distribution of lymph node metastases in patients with oropharyngeal squamous cell carcinoma and improve the rationale for elective treatment of the neck. DESIGN AND SETTING Retrospective cohort study of patients evaluated from 1990 to 1998 in a tertiary cancer care center. PATIENTS The 81 consecutive patients who were identified from the hospital database. Patients were eligible for the study if they had a previously untreated squamous cell carcinoma of the oropharynx and histopathologically diagnosed lymph node metastases without a second primary tumor treated by an en bloc resection. MAIN OUTCOME MEASURES We analyzed the anatomic distribution of lymph node metastases. RESULTS The clinical neck cancer stages were N0 in 22 cases, N1 in 22, N2a in 8, N2b in 14, N2c in 4, and N3 in 11. The most common sites for the metastases detected clinically as well as histopathologically were at levels II and III. Histologically, level I alone was involved in 5 cases and level IV alone was involved in none. Sixteen patients with N0 neck cancer stage underwent a radical neck dissection. There were 2 cases of metastases at level I and no level IV involvement. CONCLUSIONS Pathological lymph nodes in oropharyngeal squamous cell carcinoma are more frequent at level I than at level IV. This finding suggests that elective neck dissection for patients with oropharyngeal carcinoma should be a supraomohyoid neck dissection (levels I, II, and III) rather than a lateral neck dissection (levels II, III, and IV).