Steady decline in serious comorbidities among pediatric cancer survivors
medwireNews: Research presented at the 2017 annual meeting of the American Society of Clinical Oncology shows childhood cancer survivors diagnosed in more recent years can expect to experience fewer serious chronic conditions than those diagnosed in earlier decades.
Among 23,601 participants of the Childhood Cancer Survivor Study included in this analysis, the 15-year cumulative incidence of severe, disabling, life-threatening, or fatal (ie, grade 3–5) chronic health problems was 12.7% for patients diagnosed and treated in the 1970s, decreasing significantly to a respective 10.1% and 8.9% for those diagnosed in the 1980s and 1990s.
This overall decrease appeared to be driven mainly by a reduction in the cumulative incidence of endocrine conditions, declining from approximately 4% for children diagnosed in the 1970s to just over 2% for those diagnosed in the 1980s and around 1.5% among those diagnosed in the 1990s.
There was also a significant decrease in the incidence of secondary malignant neoplasms and neurologic and gastrointestinal comorbidities over time. But the incidence of other chronic conditions, such as those affecting the cardiovascular and musculoskeletal systems, remained unchanged, and indeed, there was a significant increase in hearing loss among patients diagnosed in the 1990s versus earlier periods.
Presenting author Todd Gibson (St Jude Children's Research Hospital, Memphis, Tennessee, USA) and colleagues also found a difference by diagnosis. For instance, there was a significant reduction in the incidence of serious chronic morbidity by treatment decade for survivors of Wilms’ tumor, Ewings sarcoma, Hodgkin and non-Hodgkin lymphoma, astrocytoma, and acute lymphoblastic leukemia (ALL), but not for those diagnosed with acute myeloid leukemia, neuroblastoma, soft tissue sarcoma, or osteosarcoma.
Using a standardized treatment intensity score, they showed that treatment modified the association between the decade and incidence of chronic conditions. Among Hodgkin lymphoma survivors, for example, a multivariate model unadjusted for treatment gave a hazard ratio per treatment decade of 0.75, which rose to 0.91 after adjustment.
“This indirectly suggests that treatment factors played a role in the decrease of chronic conditions over time,” Gibson told the audience in Chicago, Illinois, USA.
He concluded: “This demonstrates that the strategy of reducing treatment intensity with the goal of reducing the risk of late effects has indeed translated to improved late health outcomes for many survivors of childhood cancer.”
Speaking to medwireNews at a press conference, Gibson clarified that they had not investigated the specific changes in treatment modalities that may have led to this decrease, but they suspect that it is largely attributable to reductions in the proportions of patients receiving radiation and decreases in chemotherapy doses. The team plans to look at this aspect more closely, he said.
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