What are signs of renal cell (kidney) cancer?
Signs of renal cell cancer, the most common type of kidney cancer, include blood in the urine and a lump in the abdomen. The National Cancer Institute also lists side pain that does not go away. Loss of appetite, weight loss for no known reason, and anemia round out the list.
These and other signs may be caused by renal cell cancer or by other conditions. Renal cell cancer forms in the tubules of the kidney. Tubules are the very small tubes that filter blood, pull out waste, and make urine.
Where the kidney sits explains a lot about the symptoms. Each kidney is tucked deep in the back of the abdomen. Fat cushions it, and muscle and ribs cover it. A tumor can grow there a long time without pressing on anything a person would notice. That is why early kidney cancer is usually silent.
Doctors once taught a "classic triad" for this disease. It is blood in the urine, flank pain, and a mass that can be felt through the belly wall. Only about 10% to 15% of people ever have all three. When all three are present, the cancer is usually advanced. Waiting for the full set is a mistake. One sign alone is reason enough to be checked.
Today the picture has flipped. Nearly half of renal cell cancers are now found by accident. They turn up on a CT scan or ultrasound ordered for something else, such as belly pain, a kidney stone, or an injury. That is good news. Cancers caught this way tend to be smaller and easier to treat.
Blood in the urine deserves its own paragraph. The medical word is hematuria. It may be visible, turning urine pink, red, or the color of cola. It may also be invisible, showing up only when a lab checks a urine sample under a microscope. In the past, more than 60% of people with renal cell cancer had blood in the urine with no pain at all. Painless blood in the urine is never normal at any age. It should not be written off as a stone or an infection without testing.
Kidney tumors can also give themselves away through chemicals they release. Doctors call these paraneoplastic signs, and they may appear before any lump does. Fever, night sweats, and lasting fatigue are common ones. Lab tests may show a high calcium level, too many red blood cells, or abnormal liver results when the liver itself is fine. A new varicocele can appear as well. That means swollen veins in the scrotum, and it happens when a tumor grows into the kidney vein and blocks drainage from the testicle. In an adult man, a varicocele that shows up suddenly should be looked at.
Some things raise the odds. Smoking tobacco is the biggest one. Others are misusing certain pain medicines, extra body weight, high blood pressure, and a family history of renal cell cancer. Inherited conditions such as von Hippel-Lindau disease and hereditary papillary renal cancer also count.
Tests that examine the abdomen and kidneys are used to diagnose renal cell cancer. The usual order is a urinalysis and blood chemistry first. Then comes an ultrasound or a CT scan, sometimes an MRI, and a biopsy in selected cases. If you notice any of these signs, check with your doctor. Go to an emergency department instead if you are passing blood clots and cannot urinate. The same goes for flank pain with a fever of 100.4 F (38 C) or higher.
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Want the full picture? Read our complete explanation: What Is Kidney Cancer? Types and Signs
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