The influence of lymph node metastasis in the treatment of squamous cell carcinoma of the oral cavity, oropharynx, larynx, and hypopharynx:: N0 versus N+

Objectives/Hypothesis: Management of the N0 neck is a continuing controversy. The study compares the influence of N0 and N+ disease on the results of treating squamous cell carcinoma (SCCA) of the oral cavity (OC), oropharynx (OP), larynx (LX), and hypopharynx (HP) with five different treatment modalities. The study also compares the results of four different approaches to the treatment of the N0 neck. Study Design: A retrospective study of 3887 patients. Methods: Patients in the Tumor Research Project of the Department of Otolaryngology-Head and Neck Surgery of the Washington University School of Medicine (St. Louis, MO) with biopsy-proven previously untreated SCCA of one of the four above-mentioned regions who were treated with curative intent by one of five modalities and who were eligible for 5-year follow-up were included in the study. The treatment modalities included local resection of primary alone (LR), composite resection (primary with neck dissection) (CR), radiation therapy alone (RT), local resection with radiation therapy (LR/RT), and composite resection with radiation therapy (CR/RT). The N0 neck was treated with one of four approaches: observation with close follow-up reserving treatment only for subsequent neck disease, neck dissection, RT to the neck region, and a combination of neck dissection with RT. Multiple diagnostic, treatment, and follow-up parameters were studied using standard statistical analyses to determine statistical significance. Results: The 5-year disease-specific survival (DSS) for the all-sites group (ASG) was 59%. The DSS for the subsites included the following: OC, 53%; OP, 47%; LX, 70%; and HP, 42%. Patients with N0 disease had significantly better DSS than patients with N+ disease at all sites. Occult neck disease in NO patients was low with 4% pN1 for ASG, OC, and LX and with 11% pN1 for OP and HP. There was 3% pN2 for LX, 4% pN2 for ASG and OC, and 6% pN2 for OP and HP. The DSS for patients with occult neck disease was statistically similar to that of N+ patients. Prognostic survival indicators included age, decade of treatment, T stage, N stage, TN stage, treatment modality, and recurrence. Patients over 65 years of age had poorer DSS than younger patients. Staging T, N, and TN affected survival at all sites. Local resection produced better DSS for ASG, OC, LX, and HP patients. Local resection with radiation therapy produced increased DSS for ASG and OC patients. There was no survival advantage for HP patients related to treatment modality. Treatment of the NO neck with observation and later treatment for subsequent neck disease produced a survival advantage for patients in the ASG. This advantage was specific for ASG and LX patients staged T1NO. For patients staged T2N0, T3N0, and T4N0 at all four subsites there was no survival advantage for any of the four neck approaches. Conclusion: Lymph node metastasis significantly and negatively affects DSS in patients with SCCA of the OC, OP, LX and HP. The rate of occult neck disease (pN+) in NO patients receiving meticulous workup is low. When present, it produces DSS rates similar to those found in N+ patients. In the study series, there was decreased survival in patients older than 65 years of age, in patients with advanced tumor (T, N, TN), and in patients with recurrent disease. None of the four current approaches to treatment of the NO neck produces a significant survival advantage. Close observation with later treatment reserved for subsequent neck disease produces statistically similar survival (DSS) to the three elective (prophylactic) tratments and is a valid form of treatment. It may preclude unnecessary treatment of the neck with its attendant risks and complications. Key Words: Lymph node metastasis, squamous cell carcinoma, oral cavity, oropharynx, larynx, hypopharynx, surgery, radiation therapy, survival outcome.