Langerhans Cell Histiocytosis (LCH) in Children in the UK and Eire: An Epidemiological Survey

Jane Salotti, Vasanta Nanduri, Kevin Windebank, Jon Pritchard, Richard Lynn, Louise Parker, University of Newcastle upon Tyne, Watford General Hospital, Royal Hospital for Sick Children, Edinburgh, British Paediatric Surveillance Unit (BPSU), UK

Introduction

A two-year study was carried out to ascertain all children newly diagnosed with LCH in the UK and Eire between June 2003 and May 2005. The aims were to describe the epidemiology of LCH in the UK and Eire by age and sex, to study variation in ethnic groups and regions, to assess the interval between the onset of symptoms and diagnosis, referral patterns and outcome for the disease. 

Methods

Cases were identified using three sources of ascertainment - BPSU survey, Newcastle (NCL) postal survey and data from the United Kingdom Children’s Cancer Study Group (UKCCSG).  Clinicians who reported a case were sent a questionnaire to obtain demographic and clinical details and were sent a follow up questionnaire one year after diagnosis. 

Results

BPSU ascertained 70% of cases, NCL 60% and UKCCSG 69% (uniquely 10%, 13%, 9%). 65% of cases were reported by more than 1 clinician.  98 cases were identified giving an incidence rate (IR) of 4 per million per year in children aged 0-15 years. The IR for children aged 0-2 years is estimated to be 7.6 per million per year. 12% of cases were of mixed race or non-White origin.

33% of cases were diagnosed aged <3 years, 49% were aged 3-9 years and 16% were over 10 years of age.  The 72 cases of SS disease were bone (65), skin (3), pituitary (2), lymph node (1) and cerebrum (1). Of the bone cases 14% had multi-focal disease.  Eight of the 26 MS cases had risk organ involvement. The mean time from the first presenting symptoms to diagnosis of those with MS disease was 27 weeks and for those with SS disease 18 weeks - 17 weeks for bone, 17 weeks for skin, 23 weeks for pituitary and 25 weeks for lymph node. 90% of cases have been treated at a UKCCSG centre and 10% of cases have been managed at other hospitals.

Conclusions

The incidence rate is comparable with 4.5 per million per year aged 0-15 years in a multi-centre study in France, and the national incidence estimate for Denmark of 5.4 per million. However, our IR may be an underestimate since some cases may have ‘slipped the net’ and mild cases may never have been diagnosed. To date follow-up questionnaires have been returned for 61% of cases and the results of this study and a mortality study are expected during 2007.