In a study reported in JAMA Network Open, Bodelon et al found that survivors of first primary cancers with overweight or obesity were at increased risk for second primary cancers, particularly obesity-related cancers.
Study Details
The study focused on data from the Cancer Prevention Study II Nutrition cohort (covering 21 U.S. states), including cancer survivors who had a diagnosis of a first primary nonmetastatic invasive cancer between 1992 and 2015. Body mass index (BMI) was assessed at the time of first primary diagnosis. Cancer diagnoses were reported through biennial surveys and verified through medical records and linkage with state cancer registries.
Key Findings
The cohort consisted of 26,894 patients who received a diagnosis of a first nonmetastatic primary cancer. Mean age at first cancer diagnosis was 72.2 ± 6.5 years. At the time of first diagnosis, 11,497 participants (42.8%) had overweight, and 4,684 (17.2%) had obesity.
Median follow-up was 7.9 years (interquartile range = 3.4–13.6 years). A total of 3,749 patients (13.9%) received a diagnosis of a second primary cancer; of these patients, 1,243 (33.2%) were obesity-related second primary cancers.
Compared with patients who had a normal BMI (18.5 to < 25 kg/m2), the risk of any second primary cancer was increased among those with overweight (25 to < 30 kg/m2; adjusted hazard ratio [HR] = 1.15, 95% confidence interval [CI] =1.07–1.25) and those with obesity (≥ 30 kg/m2; adjusted HR= 1.34, 95% CI = 1.21–1.48); greater risk for obesity-related second primary cancers was observed among those with overweight (adjusted HR = 1.40, 95% CI = 1.22–1.61) and obesity (adjusted HR = 1.78, 95% CI = 1.51–2.11).
The investigators concluded: “In this cohort study of older survivors of nonmetastatic cancer, those who had overweight or obesity at the time of their first cancer diagnosis were at higher risk of developing a second cancer, especially an obesity-related second cancer. Given the high prevalence of overweight and obesity among cancer survivors, it is important to promote survivorship care guidelines recommending weight management and increase awareness of second cancers among physicians and cancer survivors.”
Clara Bodelon, PhD, MS, of the Department of Population Science, American Cancer Society, Atlanta, is the corresponding author of the JAMA Network Open article.
Disclosure: The study was supported by the Centers for Disease Control and Prevention National Program of Cancer Registries, the Surveillance Epidemiology and End Results Program cancer registries, and the American Cancer Society. For full disclosures of the study authors, visit jamanetwork.com.
