Surgical treatment of neck lymph nodes in squamous cell carcinoma of the pyriform sinus

The present study reports the results of 66 patients surgically treated for squamous cell carcinoma of the pyriform sinus between 1984 and 1996. Twenty eight patients underwent mono!ateral neck dissection and bilateral neck dissection was performed in 38 cases, for a total of 104 radical neck dissections. Of these, 73 (71%) were modified type III dissections, 17 (16%) were classical, and 14 (13%) were modified type I and II dissections. The primary lesion was strictly lateralized in 47 cases (71%), while median structures were involved in 19 patients. The primary tumor was staged pT1 in 2 patients, pT2 in 29, pT3 in 19, and pT4 in 16. The overall incidence of lymph node metastases was 79% (9 pN1, 3 pN2a, 33 pN2b, 7 pN2c) which was not correlated with T stage (50% pT1, 72% pT2, 89% pT3, 81% pT4). Occult nodal metastases were present in 42% of cases (8/19) with an incidence that increased from 11% (1/9) for pT1-2 to 70% for pT3-4 (7/10). The bilateral metastases (11%) were uniformly distributed between strictly lateral neoplasms and those tumors involving the midline. The incidence of bilateral metastases reached 19% only in patients with T4 cancers. Occult controlateral metastases were found in 12% of patients not having clinical evidence of metastases on the contra-lateral side of neck dissection (4/33). Nodal metastases never involved the I and V levels. Our data did not permit an assessment of the incidence of retropharyngeal lymph node metastases. In view of these results and considering current knowledge of the anatomy of lymphatic drainage, a selective II-IV dissection extending to the level VI on the side of the tumor appears justified in cases clinically staged as NO. In our view, when the lesion involves the posterior wall of the pharynx, neck dissection should be extended to the lateral retropharyngeal lymph nodes. Selective dissection of the controlateral side of the neck should be performed in patients having either locally advanced primary lesions or with lesions approaching the midline. In the presence of metastases which are either clinically or intraoperatively evident, neck dissection should be extended to additional lymph node levels.