More than 70% of childhood cancer survivors develop hypertension by age 50 years
Childhood cancer survivors appeared more likely to develop hypertension during adulthood than the general population, according to study results.
Todd M. Gibson, PhD, assistant member of the department of epidemiology and cancer control at St. Jude Children’s Research Hospital, and colleagues studied 3,016 adults who had survived childhood cancer for at least 10 years. Investigators assessed the prevalence of hypertension among survivors compared with the general U.S. population.
Age-specific cumulative prevalence of hypertension among childhood cancer survivors dramatically increased with age. More than 70% of childhood cancer survivors had high blood pressure by age 50 years, results showed.
Hypertension prevalence appeared substantially higher in all diagnosis groups than expected for the general population on the basis of age, sex, race or ethnicity, and BMI.
Results showed 8% of survivors had undiagnosed hypertension, whereas 22% had uncontrolled hypertension.
Nephrectomy was the only cancer therapy significantly associated with hypertension among childhood cancer survivors (OR = 1.68; 95% CI, 1.11-2.53).
HemOnc Today spoke with Gibson about the study, the implications of the results and the subgroups of childhood cancer survivors who may be at most risk for hypertension as they get older.
Question: Why prompted this study?
Answer: Some adult survivors of childhood cancer have increased risk for heart problems because of their exposure to radiation and/or chemotherapy as children. Research has shown hypertension can further increase this risk. Hypertension is an important and potentially modifiable risk factor for cardiovascular disease in everyone, but it is particularly important for childhood cancer survivors who were exposed to cardiotoxic cancer therapies, such as chest radiation and anthracyclines.
Q: How did you conduct the study?
A: We examined resting blood pressure measurements performed on 3,016 adult survivors of childhood cancer who participated in the St. Jude Lifetime Cohort Study, which included 10-year survivors of pediatric cancer treated at St. Jude Children’s Research Hospital. We identified participants with hypertension or prehypertension based on their measured blood pressure or use of antihypertensive medications. We then compared the proportion of survivors with hypertension to the proportion we would expect to observe if the survivors had the same rates of hypertension as the general U.S. population. We further examined whether survivors treated with particular childhood cancer therapies were more likely to develop hypertensive blood pressure as adults. Previous studies have generally relied on self-reported hypertension among childhood cancer survivors, but this study was the largest to use systematically measured blood pressures of survivors of many different types of childhood cancer. The key finding was that survivors of childhood cancer had a substantially higher prevalence of hypertension than what would be expected in the general population, even after taking into account important factors such as age, sex, race/ethnicity and BMI.
Q: As treatments improve and the number of pediatric cancer survivors increases, what implications will these findings have for the clinicians who care for them?
A: Some survivors of childhood cancer have increased risks for a variety of health problems later in life, including hypertension and heart disease, and these risks vary based on the specific cancer and treatments received. Many survivors do not receive dedicated survivorship care, so a key challenge is raising awareness and knowledge of the unique health care needs of survivors, both among health care providers and the survivors themselves. Treatment regimens for childhood cancer continue to evolve, so it is difficult to predict future trends, but it is notable that survivors in our study had a higher-than-expected prevalence of hypertension regardless of their specific childhood cancer diagnosis or treatment. The good news is that, unlike prior cancer therapy, high blood pressure is a modifiable risk factor. Research is needed to identify effective interventions to prevent hypertension among survivors, but our results emphasize the importance of blood pressure surveillance and management.
Q: Which particular subgroups of pediatric cancer survivors are most at risk for hypertension?
A: Although pediatric cancer survivors have an increased prevalence of hypertension due to their history of cancer and treatment, we found that the same factors that increase hypertension risk among the general population — such as older age, male sex, and being overweight or obese — also are important for survivors.
We were surprised that — in our analysis of more than 3,000 survivors, with detailed data on childhood cancer treatments — we did not find significant associations between specific treatment exposures and prevalence of hypertension with the exception of nephrectomy, which impacts a relatively small group of survivors. This suggests that the mechanisms underlying the increased prevalence of hypertension among survivors are multifactorial and warrant further study.
Q: What should clinicians do to ensure appropriate monitoring, treatment and preventive measures for this patient population?
A: The implication of our findings is that survivors of childhood cancer, and their health care providers, should pay particular attention to their blood pressure as they age. Survivors should be aware that they may experience blood pressure issues at younger ages than the general population, and the consequences of their developing hypertension may be more serious than those among individuals without a history of childhood cancer. Research is needed to identify effective interventions to prevent hypertension among survivors, which could include lifestyle behaviors — such as diet and exercise — as well as medical interventions, such as blood pressure medications. – by Rob Volansky
For more information:
Todd M. Gibson, PhD, can be reached at St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 735, Memphis, TN 38105-3678; email: firstname.lastname@example.org.
Disclosure: Gibson reports no relevant financial disclosures.