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.