Abstract
Twenty-six patients with stage I tongue cancer, who underwent excisional biopsy in our clinic between April, 1980 and December 1995, were retrospectively analyzed, focusing on the relationship between pathological findings and secondary neck metastasis (SNM) . Results obtained were as follows.
1. SNM developed in 26.9 % of 26 the cases and was found within 5-15 months after surgery. Two cases metastasized to level I, 2 cases to level II, and 3 cases to levels I & II. The number of metastasized lymph nodes was 1-5.
2. As the pathological tumor size (pT) became larger, tumor cells invaded deeper, revealing that pT in cases that invaded into the muscular layer was 13.1±2.8 mm, which was statistically significant at p<0.01 in comparison with other cases.
3. SNM developed in 20 % of 5 cases that invaded on the border of the muscular layer, and in 40 % of 15 cases that invaded into the muscular layer. However, there was no correlation between pT and SNM.
4. In regard to grading by WHO, SNM was found in 27.8 % of patients in Grade I, in 16.7 % of those in Grade II, and in 50.0 % of those in Grade III.
5. As to mode of invasion by Yamamoto, et al., no SNM developed in patients who belonged to mode 1 and 2. In mode 3 patients, however, 20.0 % developed SNM, as did 71.4 % of patients in mode 4C.
6. There was no correlation between lymphatic invasion in the resected specimens and SNM.
7. Because 7 cases that developed SNM revealed extranodular invasion pathologically, all but two cases underwent irradiation (22-54Gy), and three of them furthermore underwent chemotherapy.
8. The 5-year cumulative survival rate in this series was 71.1 %.
9. We feel that elective neck dissection should be done in cases that measure more than 10 mm in pT, that invade into the muscular layer, and belong to mode 4C (and/or 4D), even though they may be stage I tongue cancers.
