Does local hyperthermia affect metastasis of a human prostate carcinoma grown in athymic nude mice?

Primary objective: This study investigated whether local hyperthermia increases metastasis of prostate carcinoma xenografts in athymic nude mice. Research design and methods: Human prostate carcinoma cells (1-LN-PC-3-1A) were injected into the animal's thigh. Mice were randomly divided into those treated with local hyperthermia (43°C for 45 min, tumour volume 100 or 200 mm³) and untreated controls, and sacrificed when the tumour volume reached 500 mm³. Main outcomes and results: Histological evaluation (hematoxylin and eosin staining) of lymph nodes showed metastases in 20/21 hyperthermia-treated and 17/21 control mice. Lymph node involvement, tumour weight at sacrifice, and tumour growth rate were not significantly different between groups. Conclusion: Single local hyperthermia treatment had no effect on lymph node metastatic spread in this model.