[Mixed (photon-neutron) therapy in complex treatment for locally advanced breast cancer].

Long term results of treatment of patients with locally advanced breast carcinoma with the use of mixed photon-neutron therapy (PNT) are presented. Among 201 patients with locally advanced breast cancer receiving radiation therapy, in 95 of them it was implemented as a combination of photon and neutron radiation therapy and in 106--in the form of mega-volt photon therapy (PT). Comparative evaluation of the long-term results of treatment proved the superiority of PNT. The immediate effect after PNT in the form of complete and partial response of tumor was registered in 87.4%, and after PT--in 49% of cases. Five-year and ten-year survival rates without signs of disease after PNT were 58.1% and 29.5%, and after PT--36.4% and 7.4% respectively. Substantial differences in toxicity of techniques were not observed.

Optimization of an accelerator-based epithermal neutron source for neutron capture therapy.

A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the (7)Li(p,n)(7)Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine to be placed on high current IPPE proton accelerator KG-2.5. Results of calculation were experimentally tested and are in good agreement with measurements.

[Technological problems in use of fast reactors for radiotherapy of patients with malignant tumors]. / Tekhnologicheskie problemy ispol'zovaniia issledovatel'skikh reaktorov na bystrykh neítronakh dlia luchevoí terapii bol'nykh zlokachestvennymi opukholiami.

The authors discuss the technological problems associated with the use of fast neutrons in radiotherapy of cancer patients and outline the approaches to the solution of these problems. The state of the art is assessed. Physical and radiobiological prerequisites for the use of fast reactors for radiotherapy of patients with malignant tumors are analyzed. Results of clinical use of BR-10 reactor at the Medical Radiology Research Center, Russian Academy of Medical Sciences, are presented. Experimental and clinical findings indicate that the results of radiotherapy may be appreciably improved if a novel perspective source of fast neutrons, a nuclear reactor, is used.

[Fast neutrons in the treatment of malignant neoplasms]. / Bystrye neitrony reaktora v lechenii zlokachestvennykh novoobrazovanii.

More than 250 patients, mainly with locally advanced tumors of the head, neck and breast were treated with a I MeV beam of fast neutrons emitted from a BR-10 reactor. The fast neutron contribution to the total dose of the radical component of complex gamma-neutron therapy was 20-40%. Said modality was shown to improve the results of treatment for laryngeal and breast tumors. The 5-year actuarial survival following complex gamma-neutron therapy for laryngeal cancer was 89.25, while in controls--65.2% (p < 0.005). The 5-year actuarial overall survival in breast cancer patients treated with fast neutrons was 66.5%: gamma-neutron therapy alone--46.0% (p < 0.05).

[Pathomorphosis of laryngeal cancer after neutron and gamma-neutron therapy using fast neutrons of the reactor]. / Patomorfoz raka gortani pri neitronnoi i gamma-neitronnoi terapii s ispol'zovaniem bystrykh neitronov reaktora.

Studies of tumours and adjacent tissue were carried out in 29 patients with carcinoma of the larynx after preoperative irradiation with fast neurons at a total focal dose 5.6 Gy alone or in combination with gamma therapy. Pronounced pathomorphosis was established in all the cases, up to a full disappearance of the tumor in 2 patients, the degree of pathomorphosis did not depend on location, macroscopic form of growth, degree of dissemination. No changes were found in the wall of the larynx outside the tumor.

[Use of reactor neutrons in the multimodal treatment of patients with breast cancer]. / Problema ispol'zovaniia reaktornykh neitronov v kompleksnom lechenii bol'nykh rakom molochnoi zhelezy.

The results of multimodality treatment are analyzed in 56 patients with local breast cancer. Combined gamma-neutron therapy with the use of fast reactor neutrons enhances the efficiency of breast cancer treatment and does not increase the number of radiation reactions and complications. The three-year survival increased from 44 +/- 12 to 75 +/- 9%. The test reactors specifically adjusted may be useful for the radiation therapy of patients with various malignant neoplasms. Combined gamma-neutron therapy is more promising for this purpose than neutron therapy alone.

[Acute skin reactions in rats after irradiation with reactor neutrons]. / Ostrye reaktsii kozhi krys posle oblucheniia reaktornymi neitronami.

The paper is devoted to a study of acute radiation reactions of the depilated thigh skin of outbred rats after their irradiation at various doses with gamma quanta and neutrons of a BR-10 reactor with the mean energy of 0.85 MeV. A scale, developed for the assessment of a degree of severity of radiation reactions permitted quantitative interpretation of the obtained results. The RBE of neutron irradiation was 4.2.

[Dose multifractionation in radiotherapy of laryngeal cancer]. / Mul'tifraktsionirovanie dozy pri luchevoi terapii raka gortani.

A study was made of the comparative results of radiotherapy of 332 laryngeal cancer patients of whom 237 were treated by routine methods and 95 by multifractionation (double fractionation of a daily dose by 1 Gy with a 4-5 h interval). The method of dose multifractionation was mathematically substantiated. Direct efficacy of radiotherapy was assessed in the delivery of a dose of 40 Gy. A radical dose of irradiation was 66-70 Gy. At 40 Gy complete tumor resorption in the patients of the control group was noted in 33.3% of the cases, in the study group in 58.9%. The 3-year recurrence- and metastasis-free survival rate after radical radiotherapy was 47.4% in the control group and 65.3% in the study group. A decrease in the number of late postradiation edema of the laryngeal mucosa from 28.7% in the control group to 8.7% in the study group was noted.

[Teleradiotherapy of laryngeal cancer using a gas hypoxic mixture (GHM-10)]. / Distantsionnaia luchevaia terapiia raka gortani s ispol'zovaniem gazovoi gipoksicheskoi smesi (GGS-10).

A total of 96 laryngeal cancer patients were studied. A comparative analysis of short-term therapeutic results was performed in 2 similar groups: patients receiving radiotherapy without GHM-10 (50) and those receiving radiotherapy with the use of GHM-10 containing 10% of oxygen and 90% of nitrogen (46). Irradiation methods and general tactics of the patients management in both groups were identical. No differences in the short-term results were noted. Radiation reactions of the healthy tissues were less pronounced and noted less frequently in the patients on radiotherapy with the use of GHM-10.