CHICAGO – Severe health problems occurring 5 or more years after diagnosis of a childhood cancer have steadily declined, based on an analysis of 23,600 participants in the Childhood Cancer Survivor Study, funded by the National Institutes of Health.
For all childhood cancer survivors, the 15-year cumulative incidence of severe health conditions decreased from 12.7% in those diagnosed in the 1970s, to 10.1% in the 1980s, and to 8.8% among those diagnosed in the 1990s (per 10 years: hazard ratio, 0.84 [95% confidence interval, 0.80-0.89]), Todd M. Gibson, PhD, of St. Jude Children’s Research Hospital, Memphis, reported at a press conference at the annual meeting of the American Society of Clinical Oncology.
The association with diagnosis decade was attenuated (HR, 0.92 [95% CI, 0.85-1.00]) when detailed treatment data were included in the model, indicating that treatment reductions mediated risk.
Changes in childhood cancer treatment protocols to reduce the intensity of therapy – along with improved screening and early detection – have not only extended lifespan for many survivors, but also have reduced the incidence of serious chronic morbidity, Dr. Gibson said.
As the data address children diagnosed over 15 years ago, it is likely that improvements since then in determining patient risk and targeting therapy might result in further incremental improvements, he said in an interview.
By cancer type, severe health problems by 15 years after diagnosis decreased from 13% to 5% among survivors of Wilms’ tumor, from 18% to 11% among survivors of Hodgkin lymphoma, from 15% to 9% among survivors of astrocytoma, from 10% to 6% among survivors of non-Hodgkin lymphoma, and from 9% to 7% among survivors of acute lymphoblastic leukemia. The conclusions are based on the incidence of severe, disabling/life-threatening, or fatal chronic health conditions (Common Terminology Criteria for Adverse Events, grades 3-5) among 5-year survivors diagnosed prior to age 21 years from 1970 through 1999.
Adjusted for sex and attained age, significant reduction in risk over time was found among survivors of Wilms tumor (HR, 0.57 [95% CI, 0.46-0.70]), Hodgkin lymphoma (HR, 0.75 [95% CI, 0.65-0.85]), astrocytoma (HR, 0.77 [95% CI, 0.64-0.92]), non-Hodgkin lymphoma (HR, 0.79 [95% CI, 0.63-0.99]), and acute lymphoblastic leukemia (HR, 0.86 [95% CI, 0.76-0.98]).
The decreases in serious health conditions were largely driven by a reduced incidence of endocrine conditions (1970s: 4.0% vs. 1990s: 1.6%; HR, 0.66 [95% CI, 0.59-0.73]) and subsequent malignant neoplasms (1970s: 2.4% vs. 1990s: 1.6%; HR, 0.85 [95% CI, 0.76-0.96]).
Gastrointestinal (HR, 0.80 [95% CI, 0.66-0.97]) and neurological conditions (HR, 0.77 [95% CI, 0.65-0.91]) also were reduced, but cardiac and pulmonary conditions were not. Changes in childhood cancer treatment protocols have not only extended lifespan for many survivors, but also have reduced the incidence of serious chronic morbidity in this population, Dr. Gibson concluded.