cancer patient and her father
Credit: Rhoda Baer
The “health gap” between childhood cancer survivors and their siblings widens with age, according to a study published in the Journal of Clinical Oncology.
Cancer survivors aged 20 to 34 years old were 3.8 times more likely than siblings of the same age to develop new cancers and other serious health conditions.
By age 35 and beyond, survivors had a 5-fold greater risk.
“Survivors remain at risk for serious health problems into their 40s and 50s, decades after they have completed treatment for childhood cancer,” said study author Gregory Armstrong, MD, of the St Jude Children’s Research Hospital in Memphis, Tennessee.
“In fact, for survivors, the risk of illness and death increases significantly beyond the age of 35. Their siblings don’t share these same risks.”
Dr Armstrong and his colleagues uncovered these results by analyzing data from the Childhood Cancer Survivor Study, which included 14,359 survivors and 4301 healthy siblings.
The patients had been diagnosed with leukemias, lymphomas, and other pediatric cancers before age 21 and were followed for a median of 24.5 years (range, 5 to 39.3 years).
The researchers compared survivors to age-matched siblings, evaluating the incidence of severe, disabling, life-threatening, or fatal health conditions. This included new malignancies as well as diseases of the heart, lungs, liver, kidneys, and hormones.
The team found a heightened risk of these health conditions among cancer survivors. And that risk increased as the survivors aged.
At 20 years of age, 16% of survivors had serious health conditions, compared to 3.3% of siblings. But by age 50, the incidence had increased to 53.6% among survivors and 19.8% among siblings. At 50, 22.5% of survivors had at least 2 serious health problems, and 10.1% had 3 or more.
In a multivariate analysis, the hazard ratio for developing serious health conditions was significantly higher among survivors aged 35 and older than for those aged 20 to 34 (P=0.03).
Among survivors who reached age 35 without serious health problems, 25.9% developed a significant health problem in the next decade. In comparison, 6% of siblings developed their first serious health condition between the ages of 35 and 45.
In addition to showing a health gap between childhood cancer survivors and their siblings, this research adds to evidence that survivors experience accelerated aging. The 24-year-old cancer survivors had roughly the same cumulative incidence of grade 3 to 5 health conditions (19.6%) as the 50-year-old siblings (19.8%).
Overall, these findings highlight the importance of lifelong, risk-based healthcare for childhood cancer survivors, Dr Armstrong said. Depending on their cancer treatment and other risk factors, follow-up care may include performing health checks at a younger age than is recommended for the general public.
This study involved survivors whose cancer was diagnosed between 1970 and 1986. The researchers are now studying the health of adult cancer survivors from a more recent treatment era.