Microhematuria not predictive of urinary tract cancers

Microscopic hematuria demonstrated no predictive value for identification of urinary tract cancers, results of a 30-month prospective investigation showed.

Workups prompted by microscopic hematuria led to cancer diagnoses in 2.3% of patients, and only 0.3% of the diagnoses proved to be renal cancer. Multivariable analysis showed that any degree of microhematuria was least predictive of urinary cancer.

"We then analyzed a higher level of microscopic hematuria [than recommended by current guidelines], as had been suggested by our previous retrospective analysis," said first author Ronald Loo, MD, of Kaiser Permanente Downey Medical Center, Downey, CA. "Even that higher level of hematuria did not correlate nearly as well as other predictors of cancer."

The findings came from a validation study that followed the retrospective analysis, which showed that urinary tract cancers were a rare finding on follow-up of asymptomatic microscopic hematuria by current clinical guidelines.

The prospective observational study involved 4,414 patients referred to 151 urologists for evaluation of asymptomatic microscopic hematuria from January 2009 to August 2011. Dr. Loo and colleagues evaluated patient management according to the AUA Best Practice Recommendations for investigation of asymptomatic hematuria: >3 RBC/HPF on two of three urinalyses.

The workup included upper-tract imaging by multiphase computed tomography or intravenous pyelogram plus renal ultrasound and cystoscopy. Treating urologists reported history of gross hematuria within the past 6 months, imaging results, cystoscopy results, and cause of hematuria.

The findings were evaluated by means of logistic regression models that incorporated patient age, sex, degree of hematuria by urinalysis, recent history of gross hematuria, and smoking history.

The analysis identified recent history of gross hematuria and age ≥50 years as the two best predictors of a diagnosis of urinary tract cancer. Degree of hematuria (>25 RBC/HPF) had the least predictive value. Two positive urinalyses of any degree had essentially no predictive value.

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