Carcinogenesis induced by low-dose radiation

Abstract

BackgroundAlthough the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure.ConclusionsUnderstanding the molecular mechanisms of response to low dose radiation is crucial for the proper evaluation of risks and benefits that stem from these exposures and should be considered in the radiotherapy treatment planning and in determining the allowed occupational exposures.

Pulsed low dose-rate irradiation response in isogenic HNSCC cell lines with different radiosensitivity

“…Understanding molecular mechanisms of cellular response to low dose irradiation is important in order to evaluate risks and benefits of such exposure. 28 In radioresistant tumors this could provide the basis for a more tailored and effective radiotherapy. Re-irradiation of recurrent tumours in the previously irradiated areas is a feasible approach that improves survival, but is limited due to normal tissue toxicity.…”

The Risk of Second Primary Cancers in Prostate Cancer Survivors Treated in the Modern Radiotherapy Era

“…This requires a longer beam-on time and results in larger low dose volumes and more out-of-field ionizing dose to peripheral healthy tissue further away from the target (1,2). It is therefore increasingly recognized that modern RT might result in excess DNA damage in peripheral tissues, potentially increasing the risk of SPC, especially for young patients with favorable survival (3)(4)(5). To date, there are insufficient clinical data to draw firm conclusions about the impact modern RT has on SPC risks (6,7).…”

Differential expression of NPM, GSTA3, and GNMT in mouse liver following long-term in vivo irradiation by means of uranium tailings

“…Many researcher groups have provided fundamental data on the risk of ionizing radiation exposure for cancer development in humans [ 29 ]. The effects of LDR on an organism may include DNA damage and chromosome aberrations [ 30 , 31 ].…”