Microhematuria called poor predictor of bladder Ca

The presence of microhematuria does not necessarily indicate the presence of cancer, say researchers from Kaiser Permanente Southern California, Pasadena.

The study results suggest that tests routinely done on patients with microhematuria could be avoided and has led to the creation of a screening tool to better diagnose certain types of cancers.

The observational study, which will be published in the February issue of Mayo Clinic Proceedings, examined the electronic health records of more than 4,000 patients with microscopic hematuria who were members of Kaiser Permanente health plans in Southern California, Northern California, and the Pacific Northwest between January 2009 and August 2011. The authors found that an extremely small proportion of patients with microhematuria were subsequently discovered to have cancer: Among the 4,414 patients who were evaluated for the condition, 2.3% were diagnosed with bladder cancer and 0.2% had a pathologically confirmed diagnosis of renal cancer.

The authors concluded that patients with microhematuria, especially those under 50 years of age and with no history of gross hematuria, might not benefit from further evaluation.

"This study provides scientific data that confirms what others have suspected—that microscopic hematuria is an unreliable indicator of renal or bladder cancer," said lead author Ronald K. Loo, MD. "This suggests that a large number of follow-up examinations of patients with asymptomatic microscopic hematuria, which often includes radiologic and invasive procedures, could be safely avoided.

"Primary care physicians should be aware that performing follow-up examinations on patients with asymptomatic microscopic hematuria contains an element of unnecessary risk. By far, a much more reliable indicator of the presence of urinary cancer is whether or not a patient has gross hematuria," Dr. Loo added.

The authors also used the data compiled from the study to create a model to predict renal and bladder cancer risk. Called the Hematuria Risk Index, the model assigns points for specific cancer risk factors. Higher risk factors, such as a history of gross hematuria and patient age of 50 years or over, are assigned four points, while lower risk factors, such as a history of smoking and male gender, are given one point. The authors were then able to group patients into low, moderate, and high risk of renal or bladder cancer. They found that of the 32% of patients who were identified as having a low risk of cancer, only 0.2% had a cancer detected. And of the 14% of the patients who were identified as high risk, 11.1% had a cancer detected.

Look for further coverage of this study in the February issue of Urology Times.