# Temporal clustering of neuroblastic tumours in children and young adults from Scotland

## TL;DR

This study found that neuroblastic tumors in Scottish children and young adults cluster over time, suggesting possible environmental factors.

## Contribution

The study provides evidence of temporal clustering of neuroblastic tumors in Scotland using a modified statistical method.

## Key findings

- There was significant temporal clustering of neuroblastic tumors between years (EPV = 9.13, P < 0.001).
- Clustering was observed in children under 18 months between months within quarters (EPV = 0.77, P = 0.044).
- Clustering was also found in those aged 18 months–24 years between fortnights within months (EPV = 1.00, P = 0.012).

## Abstract

Neuroblastic tumours (neuroblastoma and ganglioneuroblastoma) are the most common childhood solid tumours outside the central nervous system, with a median age of diagnosis of 2 years. Temporal clustering of neuroblastic tumours in northern England and Ontario, Canada has been previously reported.

We extracted data from the Scottish Cancer Registry to determine whether there was evidence of temporal clustering of neuroblastic tumours. Cases diagnosed in children and young adults aged 0–24 years between 2000 and 2020 were analysed. A modified version of the Potthoff-Whittinghill method was used to test for temporal clustering. Estimates of extra-Poisson variation (EPV) and standard errors (SE) were derived.

One hundred and sixty-one cases of neuroblastic tumours, aged 0–24 years, were diagnosed during the study period. Overall, there was statistically significant temporal clustering between years within the full study period (EPV = 9.13, SE = 0.22, P < 0.001). In addition, for cases aged < 18 months, there was significant temporal clustering between months within quarters (EPV = 0.77, SE = 0.41, P = 0.044). For cases aged 18 months – 24 years, there was significant temporal clustering between fortnights within months (EPV = 1.00, SE = 0.47, P = 0.012).

The finding of temporal clustering is consistent with the involvement of one or more, as yet unknown, transient environmental agents in the aetiology of neuroblastic tumours.