People with kidney disease may be at increased risk of cancer, according to new findings presented at the National Kidney Foundation's 2014 Spring Clinical Meetings.

Men and women with stage 3 chronic kidney disease (CKD) were significantly more likely to be diagnosed with cancer during a five-year follow-up period than their peers with normally functioning kidneys. The research was conducted by Dhruti P. Chen, MD and her colleagues at University Hospitals, Case Western Reserve University School of Medicine, in Cleveland, Ohio.

"While our research is among the few studies which is first to show this association, it does not specifically address the mechanisms," Dr. Chen said. "We can speculate multiple possibilities -including the lack of renal clearance of solutes, which means that in patients with chronic kidney disease there are minerals and waste products that are building up and causing low grade inflammation.  The products of this inflammation may be providing the right environment or 'broth' for growth of cancer or tumor cells."

"While this study provides a unique and novel perspective on the association of kidney disease and cancer, there is certainly more research needed to look closely at which specific cancers are more prevalent and which patients may be at higher risk," Dr. Chen said.

To investigate whether kidney function and cancer risk might be linked, Dr. Chen and her colleagues analyzed data on 31,896 people participating in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). During follow-up, 2,529 of the study participants were diagnosed with cancer. People with stage 3 or higher chronic kidney disease were more likely to develop cancer, including fatal cancer, than patients with normal kidney function. The increased risk was similar for patients of all ages and races, and for men and women and people with and without diabetes.

Many people with chronic kidney disease don't know they have it, Beth Piraino, MD, President of the National Kidney Foundation, noted. "Given how important the kidney is in eliminating potential toxins from the body, it makes sense that decreased kidney function might increase the risk of cancer," said Piraino. "This is another important reason for people to take care of their kidneys."

"Important steps to take to protect the kidneys are keeping weight down, controlling blood pressure and blood sugar, not smoking, avoiding excessive use pain medications and regular exercise," added Piraino. "This study suggests that the increased risk for cancer is present even in the early stages of kidney disease, so taking those steps to reduce risk of developing kidney disease could be preserving health in numerous ways."