Kidney Cancer Detected Early With Urine Test

If kidney cancer is diagnosed early - before it spreads - 80 percent of patients survive. However, finding it early has been among the disease's greatest challenges. Now, researchers have developed a noninvasive method to screen for kidney cancer that involves measuring the presence of proteins in the urine. The findings are reported in the journal JAMA Oncology.
The researchers found that the protein biomarkers were more than 95 percent accurate in identifying early-stage kidney cancers. In addition, there were no false positives caused by non-cancerous kidney disease.
Kidney cancer is the seventh most common cancer in men and the 10th most common in women, affecting about 65,000 people each year in the United States. About 14,000 patients die of the disease annually.
Like most cancers, kidney tumors are easier to treat when diagnosed early. But symptoms of the disease, such as blood in the urine and abdominal pain, often don't develop until later, making early diagnosis difficult. When kidney cancer isn't discovered until after it has spread, more than 80 percent of patients die within five years.
The researchers analyzed urine samples from 720 patients who were about to undergo abdominal CT scans for reasons unrelated to a suspicion of kidney cancer. Results of the scans let the investigators determine whether or not patients had kidney cancer. As a comparison, they also analyzed samples from 80 healthy people and 19 patients previously diagnosed with kidney cancer.
The researchers measured levels of two proteins in the urine - aquaporin-1 (AQP1) and perlipin-2 (PLIN2). None of the healthy people had elevated levels of either protein, but patients with kidney cancer had elevated levels of both proteins.
In addition, three of the 720 patients who had abdominal CT scans also had elevated levels of both proteins. Two of those patients were diagnosed subsequently with kidney cancer, and the third patient died from other causes before a diagnosis could be made.
Each protein, or biomarker, individually pointed to patients who were likely to have kidney cancer, but the two together were more sensitive and specific than either by itself. When the biomarkers were put together, patients with kidney cancer were correctly identified and without any false positives. Even when patients had other types of non-cancerous kidney disease or other types of cancers, levels of the two proteins in the urine were not elevated and did not suggest the presence of kidney cancer.
Not all kidney masses found by CT scans turn out to be cancerous. In fact, about 15 percent are not malignant. But a CT scan can only tell you whether there is a mass in the kidney, not whether it's cancer.
The researchers are working to develop an easy-to-use screening test for kidney cancer, much like mammograms, colonoscopies or other tests designed to identify cancer at early, more treatable stages before patients have symptoms.
Based on material originally posted by Washington University School of Medicine.