According to a long-term, population-based, cohort study of childhood cancer survivors, decreased overall mortality rates and fewer deaths from cancer or the effects of treatment were observed over a 60-year follow-up.
The study, led by Miranda M. Fidler, PhD student, from the Centre for Childhood Cancer Survivor Studies at the Institute of Applied Health Research at the University of Birmingham in the United Kingdom, and authors and published in BMJ, analyzed long-term health outcomes for 34,489 five-year survivors of childhood cancer diagnosed between 1940 and 2006 who were followed until February 28, 2014. The researchers used data from national registries to track deaths and to determine how long the patient survived and the cause of death.
Overall, 4,475 deaths were observed (13% of the study population), representing a mortality rate that is 9.1 times (95% CI 8.9-9.4) what is expected in the general population and corresponding to 64.2 (95% CI 62.1-66.3) excess deaths per 10,000 person-years.
The number of excess deaths from all causes declined among those treated more recently; those treated during 1990 to 2006 experienced 70 percent fewer excess deaths than those treated before 1970. The corresponding percentages for the decline in excess deaths from recurrence or progression and non-neoplastic causes were 30 percent and 60 percent, respectively.
The longer people lived, the less likely their deaths were linked to the original cancer or a new malignancy, Dr. Fidler and authors observed. After age 60, 31 percent of excess deaths were caused by new cancers, compared with 37 percent caused by circulatory issues. Among cancer survivors in their 50s, 41 percent of excess deaths were caused by new cancers and 22 percent by circulatory conditions. Among survivors 50 to 59 years old, 41 percent and 22 percent of excess deaths were attributable to subsequent primary neoplasms and circulatory conditions, respectively, whereas the corresponding percentages among those ≥60 years old were 31 percent and 37 percent.
“The important message for evidence-based surveillance aimed at preventing excess mortality and morbidity in survivors ≥60 years [old] is that circulatory disease overtakes subsequent primary neoplasms as the leading cause of excess mortality,” the authors concluded.
Sources: Fidler MM, Reulen RC, Winter DL, et al. Long term cause specific mortality among 34 489 five year survivors of childhood cancer in Great Britain: Population based cohort study. BMJ. 2016;354:i4351; Reuters, September 9, 2016.