Evaluation of microscopic hematuria and risk of urologic cancer in female patients

Background: Urologic cancer has a lower prevalence in women compared with men; however, there are no differences in the recommended evaluation for women and men with microscopic hematuria.

Objectives: The purpose of this study was to identify risk factors that are associated with urologic cancer in women with microscopic hematuria and to determine the applicability of a hematuria risk score for women.

Study design: We conducted a retrospective cohort study within an integrated healthcare system in Southern California. All urinalyses with microscopic hematuria (>3 red blood cells per high-power field) that were performed from 2009-2015 were identified. Women who were referred for urologic evaluation were entered into a prospective database. Clinical and demographic variables that included the presence of gross hematuria in the preceding 6 months were recorded. The cause of the hematuria, benign or malignant, was entered into the database. Cancer rates were compared with the use of chi-square and logistic regression models. Adjusted risk ratios of urologic cancer were estimated with the use of multivariate regression analysis. We also explored the applicability of a previously developed, gender nonspecific, hematuria risk score in this female cohort.

Results: A total of 2,705,696 urinalyses were performed in women during the study period, of which 552,119 revealed microscopic hematuria. Of these, 14,539 women were referred for urologic evaluation; clinical data for 3573 women were entered into the database. The overall rate of urologic cancer was 1.3% (47/3573). In women <60 years old, the rate of urologic cancer was 0.6% (13/2053) compared with 2.2% (34/1520) in women ≥60 years old (P<.01). In women who reported a history of gross hematuria, the rate of urologic cancer was 5.8% (20/346) compared with a 0.8% (27/3227) in women with no history of gross hematuria (P<.01). In multivariate analysis, > 60 years old (odds ratio, 3.1; 95% confidence interval, 1.6-5.9), a history of smoking (odds ratio, 3.2; 95% confidence interval, 1.8-5.9), and a history of gross hematuria in the previous 6 months (odds ratio, 6.2; 95% confidence interval, 3.4-11.5) were associated with urologic cancers. A higher microscopic hematuria risk score was associated with an increased risk of cancer in this test cohort (P<.01). Women in the highest risk group had a urologic cancer rate of 10.8% compared with a rate of 0.5% in the lowest risk group.

Conclusions: In this female population, >60 years old and a history of smoking and/or gross hematuria were the strongest predictors of urologic cancer. Absent these risk factors, the rate of urologic cancer did not exceed 0.6%. A higher hematuria risk score correlated significantly with the risk of urologic cancer in this female test cohort.