ASN Report 2015

appear or when the expected number of cases is low,

which is the case with low exposure levels of a few tens

of millisieverts (mSv) for example, must be borne in

mind. Cohorts such as that of Hiroshima and Nagasaki

have clearly shown an excess of cancers, with the average

exposure being about 200 mSv; studies on nuclear

industry workers published in recent years suggest

risks of cancer at lower doses.

These results support the justification of radiological

protection of populations exposed to lowdoses of ionising

of current regulations. Other epidemiological work has

revealed a statistically significant rise in cancers (secondary

effects) among patients treated using radiotherapy and

attributable to ionising

radiation.We

can alsomention the

Chernobyl accident which, as a result of the radioactive

iodine released, caused in the areas near the accident

an excess in the incidence of thyroid cancers in people

irradiated during childhood.

The risk of radiation-induced cancer appears at different

levels of exposure and is not linked to the exceeding of a

threshold. It is revealed by an increase in the probability

of cancer in a population of a given age and sex. These are

then called probabilistic, stochastic or random effects.

The internationally established public health objectives

related to radiation protection aim to prevent the

appearance of deterministic effects and reduce the

probabilities of cancers arising fromexposure to ionising

radiation, which are also known as radiation-induced

(or radio-induced) cancers; the results of the studies as

a whole seem to indicate that radio-induced cancers

represent the predominant health risk associated with

exposure to ionising radiation.

1.2 Evaluation of risks linked

to ionising radiation

Themonitoring of cancers in France is based on 14 general

registers inmetropolitan France (covering 18

départements

and the greater Lille urban area) and 3 registers in the

overseas French

départements

. In addition to this, there are

12 specialised registers: 9

département

registers covering

16 continental

départements,

2 national cancer registers

for children under 15 years of age concerningmalignant

haemopathy and solid tumours, and 1 multicentric

mesothelioma register for France as a whole.

The aim of the register for a given area is to highlight

differences in spatial distribution, to reveal changes over

time in terms of increased or reduced incidence in the

different cancer locations, or to identify clusters of cases.

This method of monitoring aims to be descriptive but

is unable to highlight any causal effect between an

exposure to ionising radiation and cancers, given that

other environmental factors may also be suspected.

Furthermore, it should be noted that the

département

registers do not necessarily cover the areas close to the

nuclear installations.

Epidemiological investigation supplements monitoring.

The purpose of epidemiological surveys is to highlight

an association between a risk factor and the occurrence

of a disease, between a possible cause and an effect, or

at least to enable such a causal relation to be asserted

with a very high degree of probability. The intrinsic

difficulty in conducting these surveys or in reaching

a convincing conclusion when the illness is slow to

The conclusions of the ASN seminar

on the risks of leukemia linked to exposure

to ionising radiation

Within the framework of the ASN advisory committees of

experts in radiation protection, ASN organised a seminar

entitled

“Risks of leukemias and exposure to ionising radiation”

on 9th June 2015. It was attended by some 60 people,

members of the GPRADE* and GPMED**, representatives of

national and international research organisations, doctors,

representatives of the institutions concerned, patients’

associations and members of the ASN Scientific Committee.

The aim was to review current knowledge on the risk of

leukemia in children and adults with respect to exposure to

ionising radiation, taking into account the radiation exposure

characteristics (acute or chronic, external or internal, age at the

time of exposure, etc.) and by synthesizing known or suspected

risk factors other than radiation.

Noteworthy conclusions of the seminar were:

• the existence of sound proof that exposure to ionising

radiation is a risk factor for leukemia;

• the importance of continuing to study the incidence rate

of leukemia in infants and young children near nuclear

installations, with particular attention to the 0-4 years

age bracket, and including a fuller description of the local

population (lifestyle and mode of exposure);

• the need for greater interdisciplinarity (epidemiology,

medicine, dosimetry, statistics) and skills-sharing was also

underlined. The development of national coverage through

the cancer registers has improved the robustness of the

epidemiological studies. This information should now be

supplemented by a characterisation of the different types of

leukemia and robust dosimetric data;

• lastly, the ongoing harmonisation of the study protocols at

national and international levels with a view to conducting

joint studies must be continued in order to have greater

statistical weight, bringing increased confidence in the results.

TO BE NOTED

* Advisory Committee for Radiation Protection for Industrial

and Research Applications of Ionising Radiation and in the

Environment.

** Advisory Committee of Experts for Radiation Protection

for the Medical and Forensic Applications of Ionising Radiation.

CHAPTER 01:

NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS

ASN report on the state of nuclear safety and radiation protection in France in 2015