Numerous studies have proven that living a healthy lifestyle, including physical activity and maintaining a healthy weight, reduces the risk of several malignancies, including thyroid, postmenopausal breast, and colorectal cancers. However, our understanding remains limited on the relationship between these factors and subsequent cancer diagnoses among adults who survived childhood cancer.
To uncover more information about the association between weight and physical activity and subsequent cancer risk for childhood cancer survivors, a team of researchers devised a retrospective clinical trial including patients who had been cancer-free for at least five years. The researchers recently published their findings in JAMA Oncology.
All patients in the study had a childhood cancer diagnosis between 1970 and 1999, at age 21 or younger. All patients participated in the Childhood Cancer Survivor Study (CCSS), a nationwide retrospective cohort study that collects information on childhood cancer survivors’ long-term health outcomes. The CCSS is a comprehensive and long-term study that has significantly contributed to our understanding of the health outcomes of childhood cancer survivors. Additionally, the researchers requested body mass index (BMI) and information on physical activity from the patients. Participants self-reported these lifestyle factors when entering the cohort and provided updates at up to six times afterward.
The study enrolled 25,658 participants from the CCSS. Nearly 23,000 participants had BMI data before subsequent cancer diagnosis, making them eligible for the current study.
The analysis estimated the incidence of each cancer subtype (hematologic, solid organ, central nervous system, and skin) and specific cancer type (breast, thyroid, colorectal, meningioma) by physical activity and BMI. Among 22,716 childhood cancer survivors, 2,156 developed subsequent cancers. Participants reporting low physical activity had a greater odds of developing subsequent cancer. Further, participants with an obese BMI had an elevated incidence rate of subsequent solid organ, central nervous system, and skin neoplasms.
The study also revealed a protective association for childhood cancer survivors who reported high levels of physical activity when concerning subsequent diagnoses of solid organ, central nervous system, and skin malignancies.
The analysis linked both BMI and physical activity with subsequent meningiomas and thyroid cancer diagnosis. However, breast and colorectal cancers and hematologic malignancies were not related to either BMI or physical activity.
The authors concluded that among childhood cancer survivors, obesity conferred an increased risk of several subsequent cancer types, and physical activity reduced the risk of subsequent cancer diagnoses. The study's findings, which suggest that healthy lifestyle factors may provide a highly valuable benefit to childhood cancer survivors, even during long-term remission, are of utmost importance and should engage the interest of all healthcare professionals, researchers, and advocates in the field.
Sources: J Clin Oncol, JAMA Oncol