Selective occlusion and focal hyperthermia therapy of V-2 tumors in the rabbit hindlimb

Utilizing technology recently developed in our laboratory, hypervascular, heat-resistant V-2 tumors growing in the rabbit hindlimb were variously subjected to selective vascular occlusion by embolization with Dextran M microspheres and focal hyperthermia to minimum intratumor temperatures of 43 degrees C X 40 minutes (OH), focal 43 degrees C X 40 minutes hyperthermia alone (H), selective occlusion plus sham hyperthermia (O), and sham treatment. Regional toxicity observed consisted of skin burns and muscle fibrosis in the H and OH groups and peripheral embolization in the O alone group. Tumors subjected to a single OH treatment had significantly reduced growth rate over a 28-day period of observation compared with all other treatment groups and sham-treated controls (P less than or equal to .05). Our findings suggest that the combination of selective vascular embolization and focused hyperthermia may be useful in therapy of hypervascular, heat-resistant human tumors in anatomic locations where selective occlusion and relatively intense focal heating can be performed. The regional toxicity encountered in this model reemphasizes the need for extensive thermal mapping over the heated region.