Kidney Stones and Cancer: What's the Link?
- Kidney stones and cancer share a few symptoms, including nausea, vomiting, pain, and blood in the urine.
- The pain of kidney stones comes on rapidly and is typically more intense than cancer pain.
- A few studies have suggested that kidney stones might increase the risk for kidney cancer, but this association hasn’t been proven.
Kidney Stones and Cancer: Comparing Symptoms
Kidney stones form when urine becomes concentrated enough for minerals such as calcium and uric acid to crystallize rather than dissolving. Those crystals stick together and eventually form hard, stone-like deposits. Related: Pow! Cameron Mathison Packs a Punch After Beating Kidney Cancer by Raising Awareness for the DiseaseSome of the hallmark symptoms of kidney stones overlap those of certain cancers. Nausea and vomiting can affect people with kidney stones or stomach cancer — the type of cancer Dolly Parton was mistakenly reported to have. Pain in the back and side is a symptom of both stones and kidney cancer.
Stone Pain vs. Cancer Pain
The pain from kidney stones is intense enough to make your mind spiral into some pretty dark places. “If you’ve got a kidney stone that is obstructing a kidney, the pain can be so horrendous that people start to think all kinds of things are going on,” says Dr. Kymora Scotland, assistant professor in the Department of Urology and associate director of the Kidney Stone Center at UCLA. “Because of that, people start worrying that there’s all kinds of things going on, up to and including cancer.”
Kidney stone pain comes on suddenly and intensely. “The type of pain that people will get with cancer is in the later stages where you feel sort of a gradual increase in the pain,” Dr. Scotland says.
There are some clear differences in the quality of the pain, though. “Kidney stone pain is fairly specific. It’s pretty sharp,” Dr. Daniel Lee, assistant professor of Urology in Surgery at the Hospital of the University of Pennsylvania, tells SurvivorNet. He adds that the pain doesn’t let up, even if you shift your weight. And it’s accompanied by symptoms like nausea, vomiting, or chills.
Kidney stone pain comes on suddenly and intensely. “The type of pain that people will get with cancer is in the later stages where you feel sort of a gradual increase in the pain,” Dr. Scotland says.
When to Suspect Cancer
The one symptom that should make you pause, if you have it, is blood in your urine. A pink, brown, or red tinge in the toilet bowl could be a sign of kidney stones, but it might also be kidney, bladder, or urethral cancer. Your risk of it being cancer is higher if you are a smoker.
Bloody urine is one symptom that’s easy to mistake for something benign. Missing the real cause could be risky. “A lot of times women will go to their physician with a complaint of blood in their urine. The assumption will be that they have a urinary tract infection, and then they never get worked up beyond that,” explains Dr. Scotland. “They’re given multiple doses of antibiotics every time they come back, and in a small percentage of those women, we will later find out that they have bladder cancer.”
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“When you have blood in the urine, you should really see a urologist, even if you think it’s a urinary tract infection or something else,” Dr. Lee says. “It’s always safer to make sure it’s something benign.” Waiting could delay a cancer diagnosis, and the treatment that could potentially prolong your life.
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See either your primary care doctor or a urologist for a workup. You’ll likely undergo an imaging test such as an ultrasound, CT scan, CT urography, MRI, or an endoscopic procedure called cystoscopy.
Kidney Stones and Kidney Cancer Risk
Could having kidney stones — as Dolly Parton did — increase the risk for kidney cancer? A 2018 study linked kidney stones with an increased risk for papillary renal cell carcinoma, a cancer of the tubes in the kidneys that filter wastes from the blood. Only about 15% of all renal cell carcinomas — the most common type of kidney cancer — are the papillary type.
Dr. Scotland cautions that this study does not prove kidney stones cause kidney cancer. “An association is not necessarily evidence of a cause,” she says.
It’s possible that the two conditions simply share the same risk factors. “The biggest risks for kidney cancer are smoking or damage to the kidney,” Dr. Lee says. “If you have recurrent stones, they’ll put you at more risk for kidney damage. And smoking can put you at more risk for a stone.” Inflammation may be another shared risk, Dr. Scotland says.
It’s always a good idea to prevent kidney stones, if for no other reason than to avoid the discomfort they bring. You can avoid them by staying well hydrated and reducing the amount of salt in your diet. But avoiding stones isn’t likely to have much, if any, impact on your cancer risk. “There is some suggestion that there might be either an association or a possible link, but we need to do more studies,” Dr. Lee says.
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