An analysis of the effects of chronic low dose-rate radiation exposure on cancer focusing on the differences among cancer types

Abstract

Purpose

The effect of chronic low dose-rate radiation exposure on cancers was investigated by analyzing the data of mice experiments conducted at the Institute for Environmental Sciences (IES). This analysis focuses on the differences between malignant lymphomas and solid cancers.

Materials and methods

The analysis is conducted based on the mathematical model introduced in our previous work. The model is expanded to analyze malignant lymphomas and solid cancers separately. Using the expanded model, the effect of chronic low dose-rate radiation on malignant lymphomas and solid cancers are discussed based on their occurrences, progressions, and mortalities.

Results

Non-irradiated control group and 20 mGy/day × 400 days irradiated groups are analyzed. The analysis showed that radiation exposure shortened mean life expectancy for both malignant lymphomas and solid cancers (shorter by 89.6 days for malignant lymphomas and 149.3 days for solid cancers). For malignant lymphomas, both the occurrence and the progression are affected by radiation exposure. The mean age at which malignant lymphoma developed in mice was shortened by 32.7 days and the mean progression period was shortened by 57.3 days. The occurrence of solid cancer is also affected by radiation exposure, wherein the mean age at which solid cancer develops was shortened by 147.9 days. However, no significant change in progression period of solid cancers was seen in the analysis.

Conclusions

The analysis showed that the occurrence and mean lifespan are affected in both malignant lymphomas and solid cancers. The shortening of the progression period is only seen in malignant lymphoma, no significant change was observed in solid cancers.

Keywords:

• Mathematical model
• biological effects
• low dose rate
• life-shortening
• cancer

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was partly supported by Japan Society for the Promotion of Science JSPS KAKENHI under Grant Number 22K04987 to Y.M. and T.W.

Notes on contributors

Tetsuhiro Kinugawa

Tetsuhiro Kinugawa is a Ph.D. student in Graduate School of Engineering, Osaka University. His research topic is mathematical analysis of biological effects caused by radiation.

Ignacia Braga Tanaka

Ignacia Braga Tanaka III, DVM, Ph.D. is a Senior Researcher in Department of Radiobiology at the Institute for Environmental Sciences. Her research interests are mainly on pathology of the biological effects of low dose-rate radiation exposure.

Satoshi Tanaka

Satoshi Tanaka, DVM, Ph.D. is a Senior Researcher in Department of Radiobiology at the Institute for Environmental Sciences. His research interests are mainly on pathology of the biological effects of low dose-rate radiation exposure.

Yuichiro Manabe

Yuichiro Manabe, Assistant Professor, Doctor of Sciences (theoretical nuclear physics), is representative of interdisciplinary platform for biological effect of radiation, Collaborative Research Projects, Graduate School of Engineering, Osaka University. His research topics are simple mathematical model which give account to biological effects caused by radiation.

Fuminobu Sato

Fuminobu Sato, Ph.D. is a Professor of Graduate School of Engineering, Osaka University. His research focuses on nuclear reactor decommissioning.

Takahiro Wada

Takahiro Wada, Ph.D., is a Professor of Faculty of Engineering Science, Kansai University. His research interests lie in theoretical nuclear physics, especially the fluctuation-dissipation dynamics of nuclear fission and in mathematical model analysis of the biological effects of radiation.