О ЦЕЛЕСООБРАЗНОСТИ ПРОВЕДЕНИЯ ПОВТОРНОЙ РАДИОТЕРАПИИ ПРИ РЕЦИДИВАХ И ПРОДОЛЖЕННОМ РОСТЕ РАНЕЕ ОБЛУЧЕННЫХ ОПУХОЛЕЙ РАЗЛИЧНОЙ ЛОКАЛИЗАЦИИ

Abstract

Introduction: The development of a recurrence or a second tumor in previously irradiated patients requires, in some cases, repeated radiotherapy (reirradiation) of the previously irradiated tissue volume. In the past decades, it was widely believed that it was possible to irradiate one anatomical zone in curative doses only once (taking into account the tolerance of healthy tissues) and the issue of repeated irradiation was practically not discussed (there are only a few studies). This approach was due to the fact that the use of old technologies did not allow sufficient protection of healthy tissues surrounding the tumor, which led to severe complications. Due to the development of radiotherapy technologies and new advances in radiobiology, the number of studies on the re-irradiation of recurrent tumors has recently increased significantly, however, they are mainly retrospective in nature and do not have a sufficient evidence compared to indications for primary radiotherapy. However, reirradiation can be used not only for palliative purposes, but also to achieve long-term local control. Modern medical approaches and technical capabilities make it possible to re-irradiate tumors of any localization, up to the second curative dose. Purpose: To investigate the expediency of repeated irradiation of patients with different tumor localizations, taking into account the survival rates of patients, possible complications and subsequent quality of life. Materials and methods: For the first time in Armenia, an analysis of the results of reirradiation is carried out on the basis of the experience of one clinic. The results of treatment of 1300 patients, who received radiotherapy at the IRA MEDICAL Group Radiotherapy Center from March 2019 to March 2022 were studied. The study included 52 patients, who received the second course of RT, which accounted for 4% of the total number of patients. The median age of patients was 60.5 years (22 - 81), including 22 men, 30 women, based on pathologies: CNS tumors - 17 patients, brain metastasis - 10, gynecology - 6, head and neck tumors - 6, metastatic skeletal bone lesions - 4, breast cancer - 3, other localizations - 6. Stage of the disease: III - 7 patients, IV - 37, unclassified - 8. The mean interval between two courses of radiotherapy was 34.5 months (1.5 - 252). The median total equivalent dose from two irradiation courses is 99 Gy (56-121). Except of the patients, who received reirradiation for metastatic relapse, the total equivalent dose was 102 Gy (84–121), and the median follow-up time after reirradiation was 9 months (4–29.5). Results: The average life expectancy of patients, who died during the observation period was 6.5 months (1-23). In 7 out of 52 patients, who initially had low KPS (60%), survival was up to 3.5 months or less. After excluding these patients from further statistical analysis, the median survival of the remaining patients was 10 months (4 – 23). As of March 31, 2022, 31 patients (59.6%) are alive, with an average follow-up of 13 months (5 – 29.5). The number of post-radiation complications and the quality of life of patients were also assessed. There were no treatment related deaths or reduced quality of life in the early stages. The results of this prospective study demonstrate that the use of the latest technologies in repeat radiotherapy can improve survival and quality of life in these patients. Thanks to new technologies, it is possible to conduct a repeated course of radiotherapy even in curative doses. When planning the second therapeutic or palliative course of radiotherapy, it is necessary to carefully select patients, taking into account a number of factors related to the previous treatment and the individual characteristics of the patient. After completion of the study, we plan to create recommendations on the criteria for selecting candidates for re-irradiation.