CHICAGO—Significant improvements in treatment protocols have reduced the incidence of serious chronic late health effects in survivors of childhood cancer treatment, according to the latest analysis from the Childhood Cancer Survivor Study (CCSS). Findings from the latest investigation into the trends over the last 30 years (abstract LBA10500) were presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting, held June 2–6, and indicate a significant improvement.
The researchers found that the 15-year cumulative incidence of people reporting at least one severe health condition decreased from 12.7% among childhood cancer survivors diagnosed in the 1970s to 10.1% for those diagnosed in the 1980s to 8.8% in the 1990s.
This current investigation used the CCSS data from 23,601 survivors to evaluate the incidence of severe, disabling/life-threatening, or fatal chronic health conditions among 5-year childhood cancer survivors diagnosed before their 21st birthday from 1970 through 1999. The median age of the survivors was 28 years. The study focused on the incidence of chronic illnesses in the first 15 years after diagnosis to provide an equal timeframe for all participants, regardless of when they were diagnosed.
Comparing survivors diagnosed in the 1970s with those diagnosed in the 1990s, the occurrence of severe health problems 15 years after initial diagnosis decreased significantly from 13% to 5% among survivors of Wilms tumor and 18% to 11% among survivors of Hodgkin lymphoma. Similar trends were found with astrocytoma (15% to 9%), non-Hodgkin lymphoma (10% to 6%), and acute lymphoblastic leukemia (9% to 7%).
The decreases were largely driven by a reduced incidence of endocrine conditions. The rates of endocrine conditions were 4.0% in the 1970s compared with 1.6% in the 1990s. In terms of subsequent cancers, the rates were 2.4% in the 1970s compared with 1.6% in the 1990s. Significant reductions were also found for gastrointestinal and neurological conditions, but not cardiac or pulmonary conditions.
The investigators found that the results for specific diagnosis groups were consistent with expectations based on how treatments evolved over time in each group. “For example, adoption of risk-adapted, response-based therapies in Hodgkin lymphoma resulted in decreased treatment intensity for many children, which has translated to reductions in the incidence of serious late effects,” said Todd Gibson, PhD, assistant member of the department of epidemiology and cancer control at St. Jude Children’s Research Hospital in Memphis.
Gibson, who presented the study findings at the meeting, said in contrast, the team did not find decreases in the incidence of serious late effects in 5-year survivors of neuroblastoma. He said this was likely due to improved 5-year survival over time in children with high-risk disease, which resulted from increased intensity of treatment over time.
“In many ways, our results are a confirmation that the incredible efforts of oncologists over the past 40 years to identify less toxic therapies for curing childhood cancer have been successful. Many survivors treated in more recent decades are living healthier lives because of those efforts. However, a substantial number of survivors still experience serious late effects, so more work remains to be done,” said Gibson.