Lymph node metastasis in squamous cell carcinoma of the oral cavity: correlation between histologic features and the prevalence of metastasis.

A retrospective study was made of the correlation between preoperative clinical or histologic findings and the prevalence of lymph node metastasis in 60 patients with squamous cell carcinoma of the oral cavity who had histologically confirmed neck metastasis. Of these 60 patients, 39 with clinically N+ necks underwent immediate therapeutic neck dissection, and 21 whose necks were initially N0 but progressed to N+ during observation underwent subsequent therapeutic neck dissection. The primary site, TNM staging, histologic grade of malignancy of biopsy specimen, and location and number of histologically positive lymph nodes were reviewed in each case. The results were as follows: (1) The prevalence of neck metastasis was not significantly correlated with primary site and T stage; however, there was an apparent correlation between histologic grade of malignancy and the prevalence of neck metastasis. Patients with grade I-II histologic malignancy showed limited metastases that involved lymph nodes in levels I-II. On the other hand, patients showing grade III-IV histologic malignancy often had metastases that extended beyond level III, regardless of T stage. These results suggest that histologic grade of malignancy, as well as clinical features, must be taken into consideration when deciding whether supraomohyoid neck dissection is indicated. (2) The group that underwent subsequent neck dissection exhibited less advanced neck metastasis and a better prognosis than the group which underwent immediate neck dissection. These findings show that if they are closely followed up, it is possible to delay neck dissection in N0 patients until a neck metastasis is detected.