[Combined neutron and gamma-therapy of tongue cancer]

The authors conducted a comparative study of the electivity of various schemes of interstitial therapy with 252Cf of 37 tongue cancer patients with tumors corresponding to the clinical stage T2N0M0. The immediate, short- and long-term results of contact neutron therapy alone, by the conventional scheme of combined therapy and a new method were assessed. Interstitial neutron therapy of a primary tumor was given at the first stage, gamma-beam therapy of a primary focus and regional metastatic zones was given at the second stage. A focal dose of neutron therapy was 3.5 Gy, dose rate 10-14 cGy/h. In 5-6 days neutron therapy was followed by a course of gamma-beam therapy at a focal dose of 40 Gy. The results of the study corroborate the conclusions of clinical radiobiology to the effect that neutron therapy damages cancer cells at the first stage more than gamma-rays. This facilitates the process of reoxygenation of tumors and increases general radiosensitivity to subsequent gamma-beam therapy. A mathematical analysis of the patients' survival has shown advantages of this therapeutic method.