Late deaths and survival after childhood cancer: implications for cure

Abstract

Objectives: To investigate causes of death and survival in subjects who had survived at least five years after diagnosis of childhood cancer; to compare observed mortality with that expected in the general population; and to compare results with a corresponding cohort diagnosed earlier. Design : Retrospective cohort study. Setting : Population based National Register of Childhood Tumours. Subjects : 9080 five year survivors of childhood cancer diagnosed in Britain during 1971-85, of whom 793 had died. Comparison with corresponding cohort diagnosed during 1940-70. Main outcome measures : Cause of death established from all available sources of information (including hospital and general practitioner records and postmortem reports) and underlying cause of death coded on death certificate. Results : Of the 781 deaths for which sufficient information was available, death was attributed to recurrent tumour in 578 (74%) cases, treatment related effect in 121 (15%), second primary tumour in 52 (7%), and other causes in 30 (4%). Comparison of observed mortality with that expected in the general population indicated a fourfold excess of deaths from non-neoplasic causes. The risk of dying of recurrent tumour in the next 10 years after surviving five years from diagnosis during 1940-70 and 1971-85 fell from 12% to 8%. The risk of dying from a treatment related effect increased slightly from 1% to 2%. Conclusion : Improvements in five year survival after childhood cancer have been accompanied by a reduction in risk of dying from recurrent tumour during the subsequent 10 years and by a slight increase in risk of dying from treatment related effects. The results provide information relevant to decisions concerning balance between effective treatments and their potentially harmful effects.