Colorectal cancer (CRC) patients who are overweight or obese when diagnosed appear to face a slightly higher risk for developing a second weight-related cancer, according to research published online in the Journal of Clinical Oncology. The finding didn’t speak to the risk of CRC recurrence, only the potential for developing other cancers associated with obesity.

To assess how obesity might affect additional cancer risk post-survival, Todd Gibson, Ph.D., and colleagues at the U.S. National Cancer Institute, focused on 11,598 CRC survivors who were about age 69 on average when first diagnosed. Patient weight had been assessed prior to their initial diagnosis by means of a body mass index calculation. In all, 44 percent of the patients were deemed overweight (BMI, 25 to 29 kg/m²), while one-quarter were obese (BMI, ≥30 kg/m²).

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The researchers found that when compared with CRC survivors who had been at normal weight at diagnosis, those who had been overweight or obese faced a greater risk for developing a second obesity-related cancer down the road. A higher obesity-driven risk was identified for kidney, pancreatic, esophageal, and endometrial cancers, as well as for postmenopausal breast cancer among female CRC patients.

However, the team stressed that the actual risk that an obese or overweight CRC survivor would develop a secondary cancer remained low, even if their relative risk was almost double that of normal-weight survivors.

“The implication,” Gibson, now an assistant faculty member at St. Jude Children’s Research Hospital in Memphis, told HealthDay, “is that maintaining a healthy weight is important for cancer prevention in CRC survivors, just as it is in the general population. Our results further emphasize the importance of existing guidelines recommending healthy weight for survivors.”


  1. Gibson, Todd M., et al. “Body Mass Index and Risk of Second Obesity-Associated Cancers After Colorectal Cancer: A Pooled Analysis of Prospective Cohort Studies. Journal of Clinical Oncology. doi: 10.1200/JCO.2014.56.8444. September 29, 2014.