Radiation therapy for brain stem tumor in children

Abstract

Background. Tumors of the central nervous system occupy the first place in the structure of causes of death from malignant tumors among children. The tumors of brain stem structures account for 10 to 15% of all intracranial neoplasms in this age group. The etiology of these tumors is not completely known. Diagnosis of pathology is based on clinical manifestations and magnetic resonance imaging. Obtaining material for histological examination at this location is associated with the risk of severe neurological disorders. Despite clinical trials in search of targeted therapy, the treatment of this pathology is based on chemoradiation therapy. Purpose – to analyze the effectiveness of radiation therapy in mono-mode and in patients with the tumors of brain stem structures without intake of Temozolomide, a ccording to the results of clinical studies conducted on the basis of National Children’s Specialized Hospital «OKHMATDYT» of the Ministry of Health of Ukraine. Materials and Methods. On the basis of the National Children’s Specialized Hospital «OKHMATDYT» of the Ministry of Health of Ukraine, in the Department of Radiation Therapy of the Radiology Center during the 3-year existence, 22 people with brain stem tumor were treated on a linear electron accelerator Elekta Sinergy S. By gender: 12 boys aged 3–10 (54%), 10 girls aged 3–11 (46%). The average life expectancy of girls was longer and exceeded one year, compared with boys. The average age was 6 ± 4 years. The diagnosis in most cases was made radiologically, but 4 patients (18%) had histological confirmation. Radiation therapy was performed according to the High grade glioma protocol with total basic dose (TBD) of up to 54 Gy for 30 fractions. 2 patients received repeated radiation therapy due to the deterioration of neurological symptoms and negative dynamics on MRI. Planning of 3D-CRT, IMRT, VMAT irradiation techniques was performed on a Monaco planning system using the Monte Carlo calculation algorithm. Results. The use of radiation therapy with appropriate anti-edematous drug support, provided significant improvement in the neurological status of the child in 5–14 days from the beginning. After 4–6 weeks of control in 21 patients there was a decrease in the pathological focus compared to the original size by 17–70%. In 5 patients the tumor spread to the large hemispheres and/ or spinal cord after radiation therapy. 2 patients received repeated radiation therapy in 1 year and 1 year and 1 month after the previous one, based on the deterioration of neurological symptoms and negative dynamics on MRI. The average life expectancy was 13 months ± 7 months. It was longer for girls – more than a year, compared to boys. Conclusions. Diffuse intrinsic pontine gliomas are the leading cause of child mortality among patients with CNS tumors. Less than 10% of children live more than 2 years after diagnosis. At present, there is no method of radical treatment of patients with diffuse intrinsic point glioma. Radiation therapy still remains the main standard of treatment for DIPG, which improves the quality and duration of a child’s life.