We retrospectively evaluated the correlation between the clinicopathological features and the clinical course of patients with TxN 0 squamous cell carcinoma of the tongue. From 1987 through 1997, 54 consecutive patients treated at our department were reviewed.
1. Local or cervical recurrence and secondary metastases to the cervical lymph nodes after initial therapy were confirmed in 10 patients (18.5%) and 13 patients (24.0%), respectively. Most cases of secondary metastases occurred within 1 year after therapy. As for tumor size, a higher frequency of recurrence or metastasis was found in advanced T stage, but there was no significant relation between clinical growth pattern and clinical course.
2. Surgical treatment was mainly performed as initial therapy, and prophylactic neck dissection (PND) was done in many patients (34/54), particularly those with advanced T stage, in combination with primary tumor resection. Although concomitant PND was unrelated to overall survival rate, a high frequency of histological lymph metastases (false positive cases) was observed among patients with T 3 discases (4/9, 44.4%).
3. Secondary metastases to the cervical lymph nodes occurred mainly in the upper neck (levels I, II). There was no significant correlation of multiple metastases, or extranodal spread with outcome.
4. Biopsy specimens obtained before initial treatment were histologically evaluated according to two morphologic criteria, differentiation (DIF) and structure (STR). Both criteria yieldcd significantly higher average scores in patients with secondary metastases than in those with a good clinical course. In patients with recurrence, only the average DIF score differed significantly. Furthermore, despite small primary lesions, high grade malignancy (DIF+STR ≥6) was almost consistently associated with secondary metastases to the cervical lymph nodes (four cases of stage T 1). Our results do not necessarily demonstrate a clear correlation between clinical stage and histological grade of malignancy. Further studies should assess the true grade of malignancy and indications for prophylactic neck dissection on the basis of both clinical and histological prognostic factors.
