Complications of lung cancer radiation therapy and the preventive role of positron-emission tomography

Abstract

Timely radiation therapy (RT) has become the basis for increasing the effectiveness of patients with lung cancer (LC) treatment and survival. RT is currently being used for most of such patients, although there are no reliable criteria to predict the effectiveness of radiotherapy at the moment. A large number of serious complications of radiation therapy require its improvement. Recently, the importance of positron emission tomography (PET) for LC visualization and monitoring of treatment results has been considered, as well as for the elucidation of the optimal format in the process of RT planning. The purpose of study: to investigate the nature of the RT complications in various options of the LC course, to identify the risk factors and to assess the role of the preliminary PET with fluoride-dehydroglucose in order to reduce the number of side effects of irradiation. Materials and methods. 1071 patients with LC at the ages from 24 to 86 years (mean age 59 years) were observed (83 % of men and 17 % of women). None of the patients with LC has been previously operated. The central form of LC was noted in 79 % of the examined, peripheral – in 21 %, small cell histological variant – in 18 % of cases, and non-small cell – in 82 %, IIIA–IV stages were detected in 95 % of patients’ number. 33 % of patients received radical radiation therapy for the primary tumor, 53 % – palliative lung irradiation, 14 % – palliative radiotherapy of distant metastases. A group of 25 LC patients was formed who were RT planned with the help of PET/CT (computed tomography). The ratio of upper lobe, middle lobe, middle upper, lower lobe, middle lower and mediastinal localization was 7:6:5:4:2:1, non-small cell forms of LC were noted in ¾ of the patients’ number, and small-cell forms in ¼, the ratio of IIIA, IIIB and IV disease stages was 4:4:3. The cyclotron "Siemens-RDS-Eclipse-RD" (Germany), combined tomograph PET/CT "Biograph-64-TruePoint-Siemens (Germany) were used. Results. The side effects of radiation therapy were identified in 23 % of LC cases (22 % men and 32 % women). Among the main complications of LC it has been found (in descending order): myelodepression, pulmonary hypertension, acute radiation pneumonitis, hemoptysis, acute vascular insufficiency, radiation esophagitis, acute coronary syndrome, pulmonary fibrosis, acute cerebrovascular accident, pulmonary edema, thromboembolism of the pulmonary artery branches. The integral nature of the radiotherapy complications is associated with radiotherapy for primary tumor and palliative for distant metastases, has sexual dimorphism (radiation pneumofibrosis, esophagitis, acute vascular insufficiency, pulmonary edema) and is determined by the irradiation power (development of myelodepression, radiation esophagitis). The use of a metabolic image in PET/CT allowed us to specify the area of irradiation by including a peritumorous zone in the target. It has significantly increased the carcinocidal effect of radiation in all patients and ensured a higher survival rate of patients, avoiding cases of acute radiation pneumonitis, esophagitis and pulmonary fibrosis. Conclusions. The integral nature of the radiochemotherapy complications in LC is observed practically in every fourth patient with LC, it is associated with radical RT for the primary tumor and palliative for distant metastases, has gender specific features and is determined by the irradiation rate. PET/CT provides an increase in the radiation exposure effectiveness with a decrease in its effects on healthy lung tissue, and as the result the incidence of RT side effects is reduced. cancer of lungs; radiation therapy; positron-emission tomography

Keywords

• cancer of lungs
• radiation therapy
• positron-emission tomography