Doctors have unnecessarily removed kidneys from thousands of patients because of mistakes in diagnosing a genetic disorder that causes tumors to grow in the organs, but nonetheless leaves them functional, new research suggests.
According to the new international study, published in The Lancet, one in five individuals with kidney tumors common in patients with genetic tuberous sclerosis complex (TSC) has had a kidney removed because doctors mistakenly believed the condition was kidney cancer. In addition, 40 percent underwent some kind of surgical procedure.
But proper diagnosis could have led to treatment that would have made surgery or kidney removal unnecessary, according to lead researcher John Bissler, M.D., a nephrologist at Cincinnati Children's Hospital Medical Center and lead author of the study.
"I can't tell you how many times I've heard from patients who say their doctors told them a kidney looks bad, is full of tumors, isn't working and has to come out," said Dr. Bissler, who co-directs the Tuberous Sclerosis Clinic at Cincinnati Children's.
"But you can do studies on these patients and find out that they have normal kidney function. The kidney looks bad, but it works. Doctors are unfamiliar with tuberous sclerosis, so when they see tumors, they think it's renal cell carcinoma, perform surgeries trying to help, but before long the kidney is gone. This approach is unnecessary. Fortunately, many people come to us from around the world for a second opinion."
Up to 80 percent of TSC patients have kidney tumors that respond to a new drug that can shrink them. The Food and Drug Administration last year approved everolimus to treat noncancerous kidney tumors in TSC patients who don’t require surgery, based on the research led by the Cincinnati Children's team. TSC is caused by a genetic defect and affects approximately 40,000 Americans, with up to 80 percent developing kidney problems.
For the new study, researchers tracked 118 TSC patients at 24 treatment centers in 11 countries. Everolimus substantially shrunk tumors in 42 percent of the patients after a few months of treatment.
Cincinnati Children's is one of the largest TSC clinics in the world, treating more than 839 children and adults.