Mortality among children and young people who survive cancer in Northern Ireland

Whilst survival rates for childhood cancers are excellent, it is known that these patients have an increased risk of death from disease recurrence and other causes. We investigate patterns, trends and survival of cancers in children and young adults in N. Ireland. Materials and Methods 21 years (1993-2013) of cancer incidence data including non-malignant brain tumours from the N. Ireland Cancer Registry for persons aged 0-24 years was analysed using Joinpoint regresssion for trend and the Kaplan Meier method for survival analysis up to end 2013 with excess mortality calculated at one and five years after first cancer diagnosis using standardised mortality ratios. Results 2633 children and young people were diagnosed with cancer, 1386 (52.6%) male and 1247 female with 1139 (43.3%) aged 0-14. While trends increased over time they did not reach statistical significance except in the 15-24 age group for males and females combined. The most common cancers for age 0-14 were brain, eye and central nervous system and leukaemia with skin (including non-melanoma skin) the most common in the 15-24 age group. 59 patients (2.2%) had a record of a second cancer. Survival was high at 90.7% after 1 year, better among females and similar for older and younger groups. Although mortality in children is low overall, there was an excess mortality 24.7% (22-27.5) p<0.001 at one year and 7.3% (5.5-9.2) p<0.001 for those who survived 5 years. Excluding the primary cancer there was an excess mortality for one year survivors, with deaths twice that of the background level (SMR= 2.2 (1.3-3.0)p=0.005 and although one and a half times background levels at 5 years, the excess mortality was not significant 1.5 (0.6-2.3 p=0.269). Conclusion Whilst survival from childhood cancers is excellent, this work in common with larger studies, highlights the need for ongoing monitoring of cancer survivors. Preventable skin cancer was identified as a problem in young adults.