Subsequent mortality experience in five-year survivors of childhood, adolescent and young adult cancer in Scotland: a population based, retrospective cohort study

Aim: To assess the risk of death in patients who survive at least 5 years after diagnosis of childhood, adolescent or young adult cancer.

Patients and methods: This was a population-based retrospective cohort study using linked national cancer registry and mortality records in Scotland. The study population consisted of 5229 individuals who were diagnosed with cancer before the age of 25 years between 1981 and 2003, and who survived at least 5 years after the date of diagnosis of their primary cancer. Indirect standardisation was used to calculate mortality ratios standardised for age and sex and absolute excess risks (AERs) compared to the general Scottish population.

Results: During 58,358 person-years of follow-up, there were 359 deaths among the cohort of cancer survivors. The overall SMR was 6.1 (95% confidence interval (CI) 5.5-6.7) and AER 51 (45-58) per 10,000 person-years. Largely because of age- and sex-related differences in background mortality, SMRs were higher in patients diagnosed at 0-14 years (SMR 11.0, 95% CI 9.3-12.9) than 15-24 years (4.7, 4.1-5.3), and in females (9.2, 7.8-10.8) than males (4.8, 4.2-5.5). SMRs and AERs varied substantially by primary cancer and by underlying cause of death. In general, SMRs were little altered by standardisation for an area-based indicator of socio-economic deprivation. Adjusted for age and sex, the risk of death was significantly lower in five-year survivors diagnosed during 1998-2003 compared to those diagnosed during 1981-1985 (Relative hazard ratio, 0.54, 95% CI 0.36-0.81).

Conclusion: Long-term survivors of cancer in childhood and young adulthood remain at higher risk of mortality than the general population, although the absolute risk of death is low and the excess risk has decreased over time.