New approaches to pediatric cancer treatment in recent decades mean more than 80% of children and adolescents diagnosed with cancer now survive at least five years. Yet they’re also much more likely to face serious health issues and premature death in adulthood, and the new study, published in the journal JAMA Oncology, indicates there’s still a substantial gap in life expectancy between people who had cancer as children and those who didn’t.
Researchers from Harvard University, St. Jude Children’s Research Hospital and elsewhere developed a model to estimate the life expectancies of five-year survivors of childhood cancer between 1970 and 1999. Beginning five years after diagnosis, those who had cancer in the 70s could expect to live 48.5 years, compared to 53.7 years among those diagnosed in the 80s and 57.1 years among people diagnosed in the 90s.
“Although our findings suggest that long-term survival is expected to improve, adult survivors of childhood cancer remain at risk for a shortened lifespan,” researchers wrote.
Compared to people who did not have cancer in childhood, those estimates represent an approximately 25% shorter lifespan among survivors diagnosed in the 70s and a 19% shorter lifespan among people diagnosed in the 80s. The gap is expected to narrow to 14% among childhood cancer survivors who were diagnosed in the 90s.
The significantly shorter life expectancy among people diagnosed in the 70s is largely tied to “late recurrence and health-related late mortality risks,” the researchers said. And the narrower gap since then is likely due to changes to pediatric cancer treatments – less than 5% of patients are now only treated with radiotherapy, or radiation, while the share treated only with chemotherapy, or drugs, has risen in recent decades.
The differences in life expectancy by treatment method were stark. Among people treated with chemo alone, the life expectancy gap fell from 11 to 6 years between the 1970s and the 1990s, the study found. Among those treated with radiation alone, meanwhile, that gap fell from 21 to 17.6 years. Life expectancy gains were modest among patients treated with both chemo and radiotherapy, the study found.
“Our findings highlight the need for new therapeutic approaches for cancer diagnoses for which radiotherapy remains an integral component of local control of the disease and for the vigilant care of survivors who received radiotherapy as children,” researchers said.
The findings also suggest that adults who had cancer during childhood should closely adhere to follow-up care and reduce their risk behaviors, especially because among all groups studied, early mortality was primarily driven by subsequent new cancer diagnoses and cardiac problems.
“Although we have come a long way since the early days of pediatric oncology treatment, our work is far from complete,” doctors from Stanford University and Emory Universitywrote in a commentary accompanying the study.