[ RadSafe ] COMARE 11th Report: The distribution of childhood leukaemia and other childhood cancer in Great Britain 1969-1993
Dawson, Fred Mr
Fred.Dawson199 at mod.uk
Wed Jul 19 05:28:41 CDT 2006
COMARE 11th Report: The distribution of childhood leukaemia and other childhood cancer in Great Britain 1969-1993
The 11th COMARE report shows that childhood leukaemia and many other types of childhood cancers do not occur evenly within the population of Great Britain. There are a variety of incidence rates in different geographical and social circumstances and these differ more that would be expected than from simple random or chance variations. This uneven distribution (or clustering) occurs at all levels of population distribution throughout the country, down to very local levels such as those of electoral wards. It is not known why childhood cancers tend to cluster like this. Much attention has been given to interactions between exposure to infections and immune responses. Other possible explanations have also been considered, including exposure to environmental agents. The analyses in this report have been carried out on the largest data set of childhood cancer cases ever compiled anywhere in the world. The very large data set gives considerable confidence in the results.
The development of childhood cancer is a multi-step process, the current consensus being that two or more alterations to the genetic code of normal cells are required before malignant disease is evident. The results of the current study are at least consistent with an infection/immune system process being associated with one of these steps. This does not mean that childhood cancer can pass from child to child in the common way of most childhood infections. It implies that one of the steps on the way to the development of a childhood cancer may be a rare and unusual response to an infection. The results are also consistent with a hypothesis that the non-random distributions could be due to various distributions of other carcinogenic risk factors. It is also possible that such processes may be at work at the different steps of carcinogenesis and that they may also interact with each other. Further work should be able to address these hypotheses.
By contrast, the search for increased risk levels near to nuclear power generation sites shows no pattern of excess cases of childhood cancer close to the sites of these types of nuclear installation. The studies around nuclear installations were covered in our 10th Report (COMARE, 2005) but they are also summarised in this report for the sake of completeness.
To carry out the studies described in our 11th Report required a very large database. This was compiled over a considerable time scale. The database was constructed from the National Registry of Childhood Tumours by staff of the Childhood Cancer Research Group in Oxford. The current data set consists of 12,415 cases of childhood leukaemia and non-Hodgkin lymphoma (NHL) and 19,908 cases of children with solid tumours registered under the age of 15 in England, Wales and Scotland from 1969 to 1993 inclusive.
Press enquiries to Professor Alex Elliott, Chairman of COMARE:
Tel No: 0141-211-2942
COMARE 11 th Report "The distribution of childhood leukaemia and other childhood cancers in Great Britain 1969-1993". Chairman: Professor A Elliott. ISBN: 0-85951-578-8 (£30.00). Downloads available from www.comare.org.uk and hard copies are available from the Information Office at the Radiation Protection Division of the Health Protection Agency.
Notes for editors
In COMARE's Third Report (1989), the Committee concluded that the distribution of cases of childhood leukaemia, or other childhood cancer, around individual nuclear installations cannot be seen in a proper context in the absence of comparable information about the general pattern throughout the rest of UK. Of the five recommendations made in the COMARE Third Report, two related to this conclusion. Recommendation 4 stated that ?studies of the geographical distribution of childhood cancer incidence on a nation-wide basis be carried out ? thus enabling the patterns found around nuclear sites to be seen in the context of patterns in the rest of the UK.? Recommendation 5 of the Third Report went on to say that ?once the results of the studies outlined in Recommendation 4 are available this Committee should be asked to participate in a review of the evidence relating to the incidence of childhood cancer around nuclear installations.? The results for nuclear installations were available last year and the review of the incidence of childhood cancer around nuclear installations in Great Britain was the subject of our Tenth Report published in 2005.
Using a unique database of over 32,000 cases of childhood cancer, for the time period 1969 to 1993, analyses have been carried out at county, county district and ward level throughout Great Britain. The data were also analysed in relation to population data and socio-demographic variables. This is the largest national database on childhood cancer (in the sense that it contains details of the largest number of cases currently available for the types of analyses done here) anywhere in the world.
SUMMARY OF THE 11 th COMARE REPORT
In this report we have confirmed that childhood leukaemia occurs in a non-random pattern and in a particular socio-economic distribution. However, we have also made some new and interesting findings principally about the nature of the occurrence of childhood cancers other than childhood leukaemia. In this report many types of childhood cancers have been shown to occur in a non-random fashion and with similar socio-economic distributions to that shown by childhood leukaemia. We have discussed these new findings in terms of possible aetiologies and as requested, examined the distribution of childhood cancer around nuclear installations in the UK, where we found no general pattern of increase of these childhood diseases.
The Committee on Medical Aspects of Radiation in the Environment (COMARE) was established in November 1985 in response to the final recommendation of the report of the Independent Advisory Group chaired by Sir Douglas Black (Black, 1984). Its terms of reference are to "assess and advise Government and the Devolved Authorities on the health effects of natural and man-made radiation and to assess the adequacy of the available data and the need for further research". Over the last 20 years COMARE has published many reports and statements relating to radiation health risk, many of which are available on its web site www.comare.org.uk
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