Effects of incision and irradiation on regional lymph node metastasis in carcinoma of the hamster tongue.

The effects of incision and irradiation on regional lymph node metastasis in DMBA-induced squamous cell carcinomas of the hamster tongue are reported. Metastasis to the submandibular lymph nodes was confirmed histologically in 48.0% of the animals. The incidence of lymph node metastasis was significantly increased (65.9%) after repeated incisions of tongue carcinomas. Three gray whole-body irradiation also increased the rate of metastasis from 31.0% to 46.3%. Higher incidences of lymphatic vessel invasion after incision and concomitant lymph node metastasis in the lymphatic invasion-positive group indicated a stepwise relationship leading to an increase in lymph node metastasis after incision. Because of the high incidence of metastases and close resemblance to human carcinomas in the tumor cell deposition and establishment of metastatic foci, DMBA-induced tongue carcinoma with invasion may serve as an experimental model of human oral carcinomas.