Survivors of childhood cancer have 8.4 times higher risk of mortality

Five-year survivors of childhood cancer experience an excess risk for morbidity and mortality from original cancer and related treatment, and the risk lasts long after diagnosis, according to researchers of a recently published study.

Using data from the Childhood Cancer Survivor Study, researchers from the University of Alberta in Canada, the University of Minnesota in Minneapolis, and other U.S. sites conducted a retrospectively assembled cohort study designed to determine survival probability, mortality ratios and absolute excess risks for overall and cause-specific deaths.

The study included 20,483 five-year childhood cancer survivors diagnosed between January 1, 1970 and December 31, 1986. Participants were included in a National Death Index search for deaths that occurred between January 1, 1979 and December 31, 2002, according to the researchers.

By the end of the follow-up period, 2,821 (13.8%) survivors died; 57.5% died from recurrent disease. Mortality was 8.4 times higher for survivors than age-, sex- and year-matched controls (P<.001). Women had a higher standardized mortality ratio than men (13.2 vs. 6.7; P<.001).

Overall survival probabilities were estimated at 93.5% at 10 years, 88.1% at 20 years and 81.9% at 30 years. Risk for late mortality was slightly higher among survivors diagnosed before age four.

Standardized mortality ratios were highest for survivors of non-acute lymphoblastic leukemia, non-acute myeloid leukemia, primitive neuroectodermal tumor or other central nervous system malignancy and Ewing sarcoma. Compared with patients treated in earlier years, those treated from 1982 to 1986 had the highest standardized mortality ratio.

“Through ongoing surveillance of these survivors, we will be able to clarify the magnitude and components of this elevated risk and ascertain additional emerging patterns of late-occurring mortality,” the researchers wrote.

J Natl Cancer Inst. 2008;100:1368-1379.