Survivors of Childhood Cancer Die Earlier than the General Population, but Causes Are Similar

Five-year survival after diagnosis of childhood cancer has reached >85% in the U.S., but survivors have excess morbidity and mortality later in life, often related to delayed effects of treatment. The causes and risk factors for later mortality are not understood completely.

Researchers analyzed longitudinal data from a cohort of 34,000 5-year survivors of childhood cancer (diagnoses at age <21); patients were seen between 1970 and 1999 at 31 U.S. institutions. Data included causes of death, treatment histories, lifestyle factors (i.e., smoking, alcohol use, physical activity, and weight), and cardiovascular risk factors.

Forty years after diagnosis, cumulative all-cause mortality among cancer survivors was 23%, compared with 5% in the comparable U.S. general population. Recurrence of primary cancer accounted for 34% of deaths among 5-year survivors, usually at 5 to 9 years after diagnosis. Other health-related (vs. accidental) causes became more common in later years and resembled those in the general population (e.g., subsequent cancers, heart disease, cerebrovascular disease, sepsis, respiratory infections, renal failure) but occurred at earlier ages. Specific treatment exposures (e.g., chest irradiation and certain chemotherapies) had dose-dependent associations with excess mortality. Health-related mortality was significantly higher for survivors with unhealthy lifestyles and for survivors with both hypertension and diabetes.