Safronova O. Intensity modulated radiation therapy with the usage of different modes of fractionation in the treatment patients for prostate cancer

The thesis is dedicated to increasing the effectiveness of radiation treatment and possibilities to reduce local toxicity for patients for prostate cancer. In this study we compared the results of planning in three treatment groups of patients with using of the methods of treatment: 3D-conformal radiotherapy, IMRT techniques with classic mode fractionation and IMRT techniques with hypofractionated. Based on calculating it was proved that the indices conformity was better than 9.6 % and indices homogeneity was better than 29.0 % when using IMRT techniques. We detailed algorithm of preparation and conduct of external beam therapy using IMRT techniques with different modes of fractionation: topometric CT-scans, contouring structures, individual planning and treatment of patients with using image-guided radiation therapy (IGRT). It was determined that the implementation of this protocol using IMRT technique allows to significantly reduce the doses to the bladder to 10.3 Gy with classic mode and to 10.8 Gy with with hypofractionated and to the rectum - to 10.2 Gy with classic mode and to 9.1 Gy with hypofractionated. We developed сriteria for selecting patients for using hypofractionated depending on the presence of concomitant benign prostatic hyperplasia. It was proved that the usage of image-guided radiation therapy with the introduction of cone beam computed tomography before each fraction of radiation reduces the margin PTV from 1.2 cm to 0.8 cm. Based on clinical and laboratory studies it was find that the usage of IMRT reduces the effects of acute and late local toxicity. We proposed the dynamic monitoring of patients for early diagnosis of local or systemic recurrence; it was increased biochemical progression free survival than 23.82 %.