TY JOUR TI The Modern Concept of Using Radiation Therapy for Cancer of the Oral Cavity and the Oropharyngeal Area KW oral cancer KW oropharyngeal cancer KW new classification KW radiation therapy KW local relapse KW life expectancy JO Medical Radiology and radiation safety AU Balkanov, A.S. AU Е, С.А. PY 2020 IS 65 PB Federal Medical Biological Agency of Russia