Some survivors of childhood cancers face a continued elevated risk of premature mortality, new cancers, chronic conditions, and other adverse health conditions as they grow older, according to new findings published in the Journal of Clinical Oncology.
An increased risk for cancer and other chronic health conditions was especially associated with exposure to radiation therapy, but not chemotherapy. However, with continued screening and timely intervention, these conditions may be caught early and treated when they are more manageable, noted investigators.
“Our study underscores the importance of partnership among patients, their primary care providers, and cancer survivorship programs to ensure survivors receive necessary screening for the early detection, prevention, and treatment of conditions, including secondary cancers, resulting from lifesaving treatment,” stated corresponding author of the study Rusha Bhandari, MD, a pediatric hematologist-oncologist at City of Hope.
Study Methods and Rationale
The researchers conducted the first-ever study of childhood cancer survivors who reach the age of 50—a growing population—to determine their long-term risks. They reviewed a national database of about 40,000 patients with childhood cancer to find individuals who had survived to age 50 or beyond. They reviewed these 7,490 long-term survivors' incidence of new cancers and chronic health conditions and compared them with their siblings and the general population.
Key Study Findings
The study authors found that the subsequent 5-year mortality risk rate was 8%, 18% for 10 years, and 32% for 15 years. The overall standardized mortality ratio (SMR) was 3.2 (95% confidence interval [CI] = 3.0–3.4), but the ratio was highest in relation to mortality from new cancers (SMR = 4.7; 95% CI = 4.2–5.2).
“Some survivors should screen for conditions like breast or colon cancer at an earlier age than is recommended for the general population,” stated senior study author Saro Armenian, DO, MPH, a pediatric hematologist-oncologist at City of Hope Children's Cancer Center. “Teamwork is needed to ensure survivors receive necessary screening and preventative care for conditions, including secondary cancers.”
The study showed an increased risk among childhood cancer survivors for heart disease, whereby they were more likely to develop heart problems at 55 than their siblings at age 70. In addition to this, these survivors showed greater frailty and poorer health than their siblings.
The increased risk of further serious health conditions was primarily associated with a history of radiation exposure. Subset analysis showed similar new cancer rates for survivors as in the general population, except in the case of patients who were exposed to radiation therapy. Forty percent of subsequent cancers were attributable to radiation therapy. “Radiation causes cellular DNA damage that can lead to mutations and the development of new cancers,” Dr. Armenian said.
Survivors had an at least twofold greater risk for severe, life-threatening, or fatal chronic health conditions compared with their siblings, especially among those with a history of radiation exposure (any health condition, relative rate [RR] = 2.6; 95% CI = 2.2–3.1; multiple conditions, RR = 3.3; 95% CI = 2.5–4.4).
No associations were found between chemotherapy exposure and late serious health conditions.
On the other hand, childhood cancer survivors at age 50 were no more likely to have mental health issues than their siblings. “This mental health finding may reflect the resilience and positive mindset of our long-term survivors who have battled cancer,” Dr. Bhandari said. “This is a wonderful example of how our patients continue to inspire us as they navigate their cancer and survivorship journeys.”
Disclosure: The study was supported by the National Cancer Institute and the American Lebanese Syrian Associated Charities. For full disclosures of the study authors, visit ascopubs.org.
