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American scientists have developed a urine test that enables detection of kidney cancer before the first symptoms are noticeable. This was published in JAMA Oncology. Diagnosis of renal cancer in an early stage allows for less invasive treatment which raises survival chances.

Kidney cancer is often found by coincidence on a CT or MRI scan. “Patients don't know they have kidney cancer until they get symptoms and by then, it's often too late for a cure. Metastatic kidney cancer is extremely difficult to treat”, explains one of the authors, dr. Evan Kharasch. Even when a CT scan shows abnormalities in the kidney, the diagnosis is not unambiguous. “Currently, the only way to know for sure is to have surgery, and unfortunately, ten to fifteen percent of kidneys removed surgically turn out to be normal", Kharasch says.

In the study, the concentration of two biomarkers (aquaporin-1 and perlipin-2) was measured in the urine of 720 people who underwent an abdominal CT scan for various reasons. For comparison, the same test was performed on the urine of 80 healthy subjects and 19 kidney cancer patients. When biomarker levels were high, renal cancer could be detected with 95 percent accuracy. This was confirmed by the CT images and subsequent surgeries. The biomarker concentrations were significantly lower in the urine of healthy subjects or patients with other kidney diseases.

Although the use of aquaporin-1 and perlipin-2 for renal cancer detection has already been suggested in previous investigations, this is the first validation in a prospective study. However, it is not probable that the biomarkers will be used for population screening, since kidney cancer has a low prevalence. The test will be useful, though, for excluding renal cancer in the case of an aberrant CT scan or symptoms like hematuria.

Sources: JAMA Oncology and Eurekalert

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