modalities have been developed for treatment of internal tumors using surgical procedures, endoscopic routes or percutaneous approaches to gain access to the treatment area. hyperthermia therapy hyperthermia therapy is heat treatment for cancer that can be a powerful tool when used in combination with chemotherapy (thermochemotherapy) or radiation for the control of a variety of cancers. the heat can be applied locally to the tumor site, which will dilate blood vessels to the tumor, allowing more chemotherapeutic medication to enter the tumor. additionally, the tumor cell membrane will become more porous, further allowing more of the chemotherapeutic medicine to enter the tumor cell. hyperthermia has also been shown to help prevent or reverse "chemo-resistance." chemotherapy resistance sometimes develops over time as the tumors adapt and can overcome the toxicity of the chemo medication. "overcoming chemoresistance has been extensively studied within the past, especially using cddp-resistant cells. in regard to the potential benefit that drug-resistant cells can be recruited for effective therapy by combining chemotherapy with hyperthermia, it was important to show that chemoresistance against several anticancer drugs (e.g. mitomycin c, anthracyclines, bcnu, melphalan) including cddp could be reversed at least partially by the addition of heat. other animals chemotherapy is used in veterinary medicine similar to how it is used in human medicine.