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Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a promising treatment method in the treatment of cancer. One of the ways of analyzing the relative biological efficiency and accurate biological dose of fast neutrons in body tissues is to improve the algorithms of computational biology and mathematical modeling. A high-performance computing code was written which allows to estimate in real-time mode the biological dose of the proton component from the action of neutron radiation with an energy of 14.8 MeV. A comparative analysis of the computing performance on various video cards was also performed., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Proton therapy (PT) due to dosimetric characteristics (Bragg peak formation, sharp dose slowdown) is currently one of the most high-tech techniques of radiation therapy exceeding the standards of photon methods. In recent decades, PT has traditionally been used, primarily, for head and neck cancers (HNC) including skull base tumors. Regardless of the fact that recently PT application area has significantly expanded, HNC still remain a leading indication for proton radiation since PT's physic-dosimetric and radiobiological advantages enable to achieve the best treatment results in these tumors. The present review is devoted to PT usage in HNC treatment in the world and Russian medicine, the prospects for further technique development, the assessment of PT's radiobiological features, a physical and dosimetric comparison of protons photons distribution. The paper shows PT's capabilities in the treatment of skull base tumors, HNC (nasal cavity, paranasal sinuses, nasopharynx, oropharynx, and laryngopharynx, etc.), eye tumors, sialomas. The authors analyze the studies on repeated radiation and provide recent experimental data on favorable profile of proton radiation compared to the conventional radiation therapy. The review enables to conclude that currently PT is a dynamic radiation technique opening up new opportunities for improving therapy of oncology patients, especially those with HNC., Competing Interests: Conflicts of interest. The authors declare no conflicts of interest related to the present study.

The study is based on the results of treatment of 60 patients with locally advanced laryngeal cancer (T3-4N0-3M0) exposed to combined treatment: 31 with preoperative chemoradiothera-py, 29 thermochemoradiotherapy. Radiotherapy was performed in the hyperfractionated mode: “1 Gy +1 Gy” (every 4-5 hours) 5 times a week to 30-40 Gy in total. Local hyperthermia was performed 2 times a week before the second fraction of radiotherapy in 3-4 sessions. Eight-day courses of chemotherapy were administered in the beginning of radiotherapy by scheme: vincristine (1. 4 mg/m2 per 1day), cisplatin (20 mg/m2 2, 3, 4 days), bleomycetin (10 mg/m2 5, 6 days), cyclophosphamide (200 mg/m2 7, 8 days). Surgical treatment was performed through 2,5 3 weeks after completion of radiotherapy. Local hyperthermia intensified the course of radiation reaction on the mucous of the larynx but not significant influenced on healing of surgical wounds. Thermochemoradiotherapy compared with chemoradiotherapy raised local relapse-free survival from 75 to 93% (p = 0. 07), regional, for a group of patients with stage N1-3 from 33 to 70%, N1-2 from 40 to 78% (p = 0. 1), loco -regional from 67 to 87% (p = 0. 04). Our findings suggest the necessity for further research on the use of thermochemoradiotherapy in combined treatment of patients with locally advanced laryngeal cancer.

On November 23, 2015 in Protvino of the Moscow Region there was begun proton therapy using Russia's first medical therapeutic complex "Prometheus" produced by JSC "PRO- TOM" and certified to treat patients with head and neck tumors. The complex allows irradiating patients with active scanning beam. Energy of beam is 30-250MeV and maximum field size is 10 cm vertically and 40 cm horizontally. The manufacturer declared parameters were confirmed during preclinical stud- ies. By April 8, 2016 the successful proton therapy received 20 patients with complex "targets" mostly located, from the point of view of radiation tolerance, near the critical structures.

The combined treatment with preoperative chemoradiotherapy (CRT) was performed in 28 patients with locally advanced laryngeal cancer (T3-4N0-3M0). Radiation therapy (RT) was carried out according to the scheme "1 + 1 Gy" (interval 4-5 hours) 5 times a week till 30-40 Gy. RT was accompanied by simultaneous polychemotherapy: vincristine (1.4 mg/m² per day), cisplatin (20 mg/m²--2-4 days) bleomicetin (10 mg/ m²--5, 6 days), cyclophosphamide (200 mg/m²--7, 8 days). Surgical treatment was carried out in 2.5-3 weeks after CRT. CRT allowed conducting organ-saving surgery on the larynx in 11 (52%) of 21 patients with T3 of primary tumor. All other patients underwent laryngectomy at a different volume. Five-year disease-free survival for the whole group in total (T3-4) was 88%. Relapses of regional metastases (MTS) occurred in 7 of 9 patients including in 4 of 5 patients after lymphadenectomy. The overall survival of patients with T3N02 was 71%, with T4N0-3--20%. Thus we have developed a method of treatment allowing to achieve high local relapse-free survival in patients with locally advanced laryngeal cancer. However organ-saving effectiveness of preoperative CRT and its effect on regional MTS remain low, which requires further research in this direction.

This study presents the short-term outcomes of conformal external beam radiation therapy given in conjunction with hormone therapy to 110 patients with prostate cancer. We performed a comparative analysis of the rate and degree of radiation reactions and complications following delivery of a total dose of 70 Gy and 72-76 Gy to the tumor. In prostate cancer, a continuous course of dose-escalated conformal radiation therapy resulted in satisfactory tolerance and acceptable levels of late complications.