Radiation effects of a CT scan on chromosomal aberrations in cancer and non-cancer patients

Abstract Computed tomography (CT) is indispensable in clinical practice, but the health risks of repeated low-dose radiation exposure remain unclear, especially in relation to potential differences between cancer and non-cancer patients. This study aimed to examine potential differences in biological responses to CT-associated low-dose irradiation between non-cancer patients and patients with hepatocellular carcinoma (HCC). In a prospective observational study, chromosomal aberrations (CAs) in peripheral blood lymphocytes (PBLs) were quantified by fluorescence in situ hybridization analysis with peptide nucleic acid probes (PNA-FISH). Data from 60 non-cancer patients obtained in our previous study were used as control, and 61 HCC patients were newly enrolled. Baseline CA frequencies were significantly higher in HCC patients (30.6 per 1000 cells) than in non-cancer patients (5.6 per 1000 cells; P 0.0001). Among the 61 HCC patients, those with a history of radiotherapy (RT) exhibited higher baseline CAs (64.8 per 1000 cells) compared with those without RT (n = 49; 22.2 per 1000 cells). In RT-negative HCC patients, a history of TACE also correlated with increased baseline CAs (P 0.05), suggesting a contribution of prior genotoxic therapies. In HCC patients without prior RT, a history of TACE also correlated with increased baseline CAs (P 0.05), suggesting a contribution of prior genotoxic therapies. In addition, Notably, CT-induced CA formation was greater in HCC patients with prior RT than in patients without RT (P 0.05). These results support careful assessment of cumulative medical radiation exposure in cancer patients who undergo repeated imaging and/or treatment.