Does the combination of hyperthermia with low LET (linear energy transfer) radiation induce anti-tumor effects equivalent to those seen with high LET radiation alone?

The combination of hyperthermia with low LET (linear energy transfer) radiation may have similar anti-tumor effects as high LET radiation alone. This pre-clinical study determined the optimal heating temperature and time interval between radiation and heat to achieve this equivalent effect. C3H mammary carcinomas (200 mm Previous published results in this tumor model reported that carbon ions were 1.3-1.7 times more effective than low LET radiation at inducing tumor control. Similar enhancements occurred with a temperature of only 41.0 °C with a simultaneous heat and radiation treatment. However, higher temperatures were needed with the introduction of any interval; at 42.5 °C, the enhancement was 2.5 with a simultaneous treatment, decreasing to a value within the carbon ion range with a 4-hour interval. Combining hyperthermia with low LET radiation can be as effective as high LET at inducing tumor control, but the temperature needed depended on the time interval between the two modalities.