National Academy of Medical Sciences of Ukraine
State Institution "The National Research Center for Radiation Medicine"


ISSN 2313-4607 (Online)
ISSN 2304-8336 (Print)

Problems of Radiation Medicine and Radiobiology

  
 

   

N. Maznyk, T. Sypko, V. Starenkiy, N. Bohatyrenko, N. Bilozor

State Institution Grigoriev Institute for Medical Radiology of National Academy of Medical Science of Ukraine, 82 Pushkinska St., Kharkiv, 61024, Ukraine

CYTOGENETIC DAMAGES IN LUNG CANCER PATIENTS TREATED BY EXTERNAL RADIATION THERAPY

Objective. to estimate the chromosome type aberrations outcome in lung cancer patients during radiation therapy course depending on radiation energy.
Materials and methods. Chromosome aberrations were studied in 16 lung cancer patients examined before treatment in the middle and at the end of external gamma-radiotherapy 60 on ROCUS-AM and megavolt therapy on linear accelerator Clinac 600C.
Results. The radiation-induced chromosome aberrations outcome in lung cancer patients during radiotherapy with different irradiation sources was studied. The over-spontaneous excess of chromosome type aberrations in cancer patients before treatment was shown. The similar and different features of cytogenetic damage accumulation during radiation therapy regarding to radiation type was displayed. The cytogenetic damage frequency raised during the course of therapeutic exposure in both studied groups. At the same time, the growth rate depended on the irradiation regimen and was higher for patients undergoing 60Co gamma-therapy. The different range of cells with unstable chromosome aberrations from the beginning to the end of the radiation therapy course was displayed. In the middle of the course the number of aberrations per aberrant cell was similar 15 damages for gamma therapy, 14 damages for megavoltage therapy. At the end of treatment the maximum of 10 aberrations per aberrant cell for ROCUS-AM and in 5 aberrations per aberrant cell for linear accelerator was observed. During radiotherapy the distributions of radiation-induced chromosome aberrations was found to be over-dispersed according to Poisson statistic in both patients groups.
Conclusions. The study of chromosome type aberration revealed the particularities of cytogenetic damages outcome during radiotherapy course depending on the irradiation source used. The more pronounced genotoxic effect in blood lymphocytes of lung cancer patients due to gamma-irradiation with ROCUS-AM was demonstrated despite the higher radiation energy used on a linear accelerator. Therefore, in radiation treatment effects estimation it is necessary to take into account not only the radiation quality and energy, but also the source, regimen and pre-radiotherapy procedures. The data obtained can contribute to the assessment of the consequences of local fractionated irradiation and to the development of a reference biodosimetry system in radiation therapy.
Key words: chromosome type aberrations, lung cancer patients, external radiation therapy, biological dosimetry.

Problems of Radiation Medicine and Radiobiology.
2019;24:411-425. doi: 10.33145/2304-8336-2019-24-411-425

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