This study evaluated the prognostic significance of the clinical growth pattern of squamous cell carcinoma (SCC) of the tongue. Two hundred six patients with surgically treated T1 and T2 tongue SCC were evaluated clinicopathologically. There were 114 males and 92 females who ranged in age from 21 to 85 years old. According to the UICC classification (1997), there were 106 patients classified as T1 and 100 as T2. One hundred sixty-three patients were classified as N0, and 43 patients had clinically positive nodes. Based on the surgeon's close inspection and digital palpation at the primary site, clinical growth pattern was classified into three types: superficial, exophytic and endophytic. Superficial tumor is an erythroplakic or leukoplakic lesion lacking deep induration. Exophytic tumor is a papillary or granular lesion with moderately deep induration. Endophytic tumor is an ulcerative or indurative lesion with extensive deep induration.Thus, tumors were classified into 51 (24.8%) of the superficial type, 37 (18.0 %) of the exophytic type, and 118 (57.3%) of the endophytic type.
Almost all superficial tumors were 5 mm or less in thickness and were accompanied with pericancerous epithelial dysplasia on histologic sections. On the other hand, endophytic tumors were more likely to infiltrate diffusely into the deep portion. Exophytic tumors showed intermediate malignancy between the superficial type and endophytic type. Local recurrence was most likely to occur in superficial tumors correlating with the presence of pericancerous epithelial dysplasia. Neck metastasis was developed in 3.9% of superficial tumors, 16.2% of exophyic tumors, and 56.5% of endophytic tumors. The clinical growth pattern was a significant indication for predicting neck metastasis. Five-year cause-specific cumulative survival rates were 100.0% in the superficial type, 90.5% in the exophytic type, and 80.6% in the endophytic type (p<0.01) . Thus, clinical growth pattern is a simple and useful classification to grade malignancy of early tongue SCCs.