Genitourinary malignancy among patients presenting with microscopic hematuria in Northwestern Ontario

Microscopic hematuria (MH) may indicate an underlying genitourinary (GU) malignancy. Accordingly, MH workup is essential to mitigate GU cancer-related morbidity and mortality. This study aimed to evaluate the etiologies of MH in Northwestern Ontario, Canada.

We conducted a retrospective cohort chart review of 2545 patients referred to our institution for MH from 2010-2020. Demographic and clinical data were collected. Low- and high-grade MH were defined as ≤25 and >25 red blood cells (RBCs) per high-power field (HPF), respectively.

The prevalence of GU cancer was 5.2% among patients with MH; the majority of cases (108/133, 81.2%) were identified during the initial workup, with urothelial carcinoma of the bladder being the most common subtype (81.2%). GU cancer was significantly associated with male sex (odds ratio [OR] 2.958, p<0.001), older age (OR 1.033, p<0.001), history of gross hematuria (GH) occurring more than 12 months prior (OR 3.469, p<0.001), prior lower urinary tract symptoms (LUTS, OR 0.081, p=0.014), and high-grade MH (>25 RBC/HPF, OR 2.977, p<0.001). High-grade GU cancer was significantly associated with male sex (OR 3.012, p<0.001), older age (OR 1.033, p<0.001), prior GH (OR 4.195, p<0.001), and history of LUTS (OR 0.088, p=0.016).

In our cohort, the prevalence of GU malignancy among patients with MH was 5.2%. Significant associations were observed with male sex, older age, and prior GH. High-grade MH was linked to increased GU cancer risk, emphasizing the importance of followup even in patients with low-grade MH, with prioritization given to those with high-grade MH.