In a study reported in JAMA Oncology, Joffe et al examined the association of high body mass index (BMI) and low physical activity with increased risk of subsequent neoplasms among childhood cancer survivors.
Study Details
The study involved data on 5-year survivors of childhood cancers diagnosed at < 21 years of age in the Childhood Cancer Survivor Study (CCSS) between 1970 and 1999; survivors were followed through September 2019. Analyses consisted of self-reported time-varying BMI and maximum reported physical activity (metabolic equivalent of task hours/week [MET-h/wk]) prior to development of any subsequent neoplasm, with assessments at cohort entry and up to six times thereafter. Risks adjusted for demographic and clinical variables were estimated for any subsequent neoplasm; neoplasm subtypes consisting of hematologic, solid organ, CNS, and skin; and specific neoplasms consisting of breast, thyroid, colorectal, and meningioma.
Key Findings
Among 22,716 CCSS participants with required data (of a total of 25,658), 2,554 subsequent neoplasms developed in 2,156 participants (56.7% female); median age at subsequent neoplasm diagnosis was 37.4 years (range = 13.7–63.3 years).
Survivors reporting lower physical activity had higher 30-year subsequent neoplasm cumulative incidence: 18.6% (95% confidence interval [CI] = 17.0%–20.3%) for 0 MET-h/wk (lowest) vs 10.9% (95% CI = 9.9%–12.1%) for 15 to 21 MET-h/wk (highest). Highest vs lowest physical activity was associated with significantly reduced risk for any (relative risk [RR] = 0.61, 95% CI = 0.53–0.71), solid organ (RR = 0.65, 95% CI = 0.52–0.83), CNS (RR = 0.50, 95% CI = 0.35–0.70), and skin (RR = 0.72, 95% CI = 0.60–0.86) subsequent neoplasms.
Obese vs normal BMI was associated with significantly increased risk of solid organ (RR = 1.22, 95% CI = 1.01–1.46), CNS (RR = 1.47, 95% CI = 1.12–1.95), and skin (RR = 1.30, 95% CI = 1.13–1.50) subsequent neoplasms.
For the specific subsequent neoplasms examined, BMI and physical activity were significantly associated with risk of subsequent meningiomas and thyroid carcinomas, but not breast or colorectal cancers. For obese vs normal BMI, RRs were 1.48 (95% CI = 1.09–2.00) for meningiomas, 1.64 (95% CI = 1.15–2.34) for thyroid carcinomas, 0.97 (95% CI = 0.69–1.36) for breast cancers, and 0.86 (95% CI = 0.42–1.76) for colorectal cancers. For highest vs lowest physical activity, RRs were 0.51 (95% CI = 0.35–0.75) for meningiomas, 0.53 (95% CI = 0.34–0.83) for thyroid carcinomas, 0.86 (95% CI = 0.58–1.29) for breast cancers, and 0.73 (95% CI = 0.33–1.61) for colorectal cancers.
The investigators concluded: “Among childhood cancer survivors in this cohort study, obesity was associated with an increased risk for multiple subsequent neoplasm types, while higher physical activity was associated with reduced subsequent neoplasm risk. Lifestyle interventions should be considered in future subsequent neoplasm prevention research.”
Lenat Joffe, MD, MS, of Northwell, New Hyde Park, NY, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was supported by the National Cancer Institute. For full disclosures of all study authors, visit jamanetwork.com.
