Evidence for an infectious aetiology associated with cancer amongst 15-24 year olds in England, 1996-2005


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Marlous van Laar1, Sally Kinsey2, Sue Picton2, Richard Feltbower1
1University of Leeds, Leeds, UK, 2Leeds Teaching Hospitals NHS Trust, Leeds, UK

Background

There is increasing evidence that environmental factors, such as infections, occurring around the time of cancer diagnosis or the time of birth may affect subsequent development of childhood cancer; few studies have examined whether this is true for teenagers and young adults (TYA). We aimed to develop a hypothesis around the aetiology of teenagers and young adults by analysing monthly seasonality of diagnosis and birth amongst 15-24 year olds diagnosed with cancer in England.

Method

Cases were derived from the national TYA cancer register, covering diagnoses of leukaemia, lymphoma and central nervous system (CNS) tumours (1996-2005). Incidence rates and trends were assessed using Poisson regression. Seasonality of diagnosis and birth was assessed using Poisson and logistic regression respectively with cosine functions of varying periods whilst adjusting for sex. The birth seasonality analysis was adjusted for month-specific birth populations from 1972 to 1990.

Results

There were 6251 cases diagnosed with leukaemia (n=1299), lymphoma (n=3070) and CNS tumours (n=1882), the overall incidence was 92 (95% CI 89-96) per 1,000,000 population (15-24 year olds) per year.

We observed significant evidence of a 12 monthly seasonal effect around the time of diagnosis for Hodgkin's lymphoma (P<0.001) with a peak in February, and a 6 monthly seasonal effect at time of diagnosis for the ‘other CNS tumours' group (P=0.010) with peaks in December and June. Seasonality by month of birth was evident for those with ‘other Gliomas' (Gliomas other than Astrocytoma and Ependymoma) with peaks in May and November (P=0.015).

Conclusion

Our findings support an infectious aetiological hypothesis for certain subgroups of TYA cancer in England. Further work will examine correlation with specific infections occurring around the time of birth and diagnosis.