[Sentinel lymph node in oral and oropharyngeal epithelial tumors]

Carcinomatous metastases in regional lymph nodes worsen substantially the prognosis of patients with oral cavity and oropharyngeal cancer. Due to the high probability of occult metastasis (about 30%), during surgical resection of the primary tumor usually also elective dissection of lymph nodes is performed. Opinions on the extent of the elective neck dissection still differ, whereas selective dissection increasingly gains in importance. The aim of selective dissections, based on the predictability of formation of metastases, is the identification and exstirpation of the sentinel lymph node. In this prospective study the applicability of the concept of the sentinel lymph node in patients with oral cavity and oropharyngeal cancer was analysed. 12 patients with oral cavity and orophangeal cancer, staging T1-T3, all N0 (examined by palpation and sonography) were included. The localization of the sentinel(s) was determined preoperatively by radioisotope (Tc Nanocolloid). Sentinel(s) were identified first with a gamma probe (Neoprobe 2000); we then injected methylene blue into the peritumoral area for easier detection of the sentinel(s). The sentinels were removed and sent for frozen section examination. Regardless of the findings of the frozen section examination modified dissection was carried out. Later we compared frozen sections with paraffin microtome sections of sentinel(s) and of other exstirpated neck lymph nodes. We could identify the sentinel lymph node in all patients, in 6/12 patients we found several sentinels. If sentinels were not affected by tumor cells, there were no metastases in the downstream neck lymph nodes either. If in the sentinel lymph nodes no metastases can be determined, eliminating the environment alone could be sufficient. However, this assumption requires verification in a larger patient group.