Intensification of Radiation Therapy with Control of the Amount of Radiation Using MRI in Patients with Squamous Cell Carcinoma of the Anal Canal

. The increase in the number of cured patients with squamous cell anal carcinoma and the quality of life is directly related to the improvement of radiotherapy departments technical equipment in oncological clinics. Purpose. One of the main tasks of improving technics and technology is reducting duration of chemoradiation therapy, and also number and duration of interruptions, plus more accurate determination of the tumor volume by using modern diagnostic methods, such as MRI, and creating the possibility of maximum impact on the tumor and identified affected lymph nodes while limiting dose to organs at risk. Materials and methods. During the period from 2000 to 2015 year, 301 patients with squamous cell anal carcinoma, stage T1–4N 0–3M0–1, were treated by radiation therapy with 2D-RT, 3D-CRT, or IMRT in a total dose of 50–60 Gy, in combination with chemotherapy and local hyperthermia. Results. The use of IMRT with MRI in comparison with 3D-CRT resulted in an increase of frequency of complete tumor response (at the time of first diagnostic control) up to 67.5 % (p = 0.071); reduction of frequency of interruptions in the treatment course up to 48 % (p = 0.005); significantly increased the 3-year overall survival rate to 92.9 % (p = 0.050), distant metastases — free survival — 91.0 % (p = 0.049), with a trend of improvement in locoregional control — 89.9 % (p = 0.179). Conclusions. The use of radiation therapy in its modern version, modern methods of visualization of tumor lesions and critical structures has reduced the interruptions in the course of treatment, achieved high immediate and long-term oncological results.