Editorial Comment on “Decision Curve Analysis‐Based Risk‐Adaptive Strategy for Individualizing Cystoscopy Decisions in Patients With Primary Microscopic Hematuria”

According to international guidelines, microhematuria (MH) is defined as the presence of > 3 red blood cells per high-power field on microscopic evaluation of a single, properly collected urine specimen. Screening studies estimate the prevalence of MH among healthy volunteers to range from 2.4% to 31.1% [1]. According to the most recent AUA guidelines, patients presenting with MH should be stratified as low/negligible-, intermediate-, or high-risk for genitourinary malignancy depending on the presence of risk factors that include the degree and persistence of hematuria, age, and smoking history [1]. Cystoscopy and imaging as diagnostic tests for MH are only recommended for intermediate- and high-risk patients, considering the invasiveness of the procedure, the added cost, and the relatively low detection rate of malignancy in low-risk patients. With regard to the necessity of cystoscopy, studies have reported a low yield (less than 1%) when cystoscopy is performed in low-risk patients (younger than 40 with no risk factors for bladder cancer) presenting with nonvisible asymptomatic hematuria [2]. Indeed, a recent retrospective study revealed a 3.3% (34 of 1018 patients with MH) urinary tract malignancy rate. All 34 patients with malignancy were intermediate (43.9%) or high-risk (34.6%) [3]. There is clearly a need for a more precise stratification of risk and a patient-tailored diagnostic algorithm for patients with MH. Toward this end, Acpinar et al. [4] in this issue of the International Journal of Urology explore risk-adaptive strategies based on decision curve analysis (DCA) for individualizing cystoscopy decisions in patients with MH, aiming to reduce unnecessary cystoscopies while not jeopardizing detection of bladder tumors. Multivariate analysis of data from 846 patients who underwent cystoscopy for MH identified risk factors for bladder tumors, and DCA was used to evaluate the net benefits of different strategies. Bladder tumors were detected in 66 patients (7.8%). Risk factors that increased bladder tumor detection were smoking status, pack-years of smoking, and advanced age. Factors that decreased bladder tumor detection were concurrent lower urinary tract symptoms (LUTS) and a history of recurrent urinary tract infections (UTI). The results of the study by Akpinar et al., although single-center and retrospective in nature, largely corroborate those of the IDENTIFY study, a large prospective observational study of 10 282 patients from 26 countries referred to secondary care with hematuria [5]. The almost double prevalence for bladder cancer, 17.2% versus 7.8% in the study by Akpinar et al., is attributed to the fact that the study included both gross and MH. The final model incorporated all relevant parameters, both predictors of increased risk (visible hematuria, age, smoking history, male sex, and family history) and of reduced risk (previous hematuria investigation, UTI, dysuria/suprapubic pain, anticoagulation, catheter use, and previous pelvic radiotherapy). The model proposed by Akpinar et al. achieved a c-statistic, or area under the receiver operating curve of 0.86 and is therefore considered to have good discriminatory ability in clinical practice. The added value of the study by Akpinar et al. to the IDENTIFY model is the quantification of smoking burden and confirmation of the significance of the presence or absence of irritative LUTS. Indeed, the authors concluded that a strategy that reserves cystoscopy for patients with MH and > 10 pack-years of smoking and/or no irritative LUTS provided the highest net benefit, avoiding 32% of unnecessary cystoscopies without missing any bladder tumors. Incorporating smoking severity and LUTS into the decision-making algorithm for endoscopic evaluation of MH improves risk-stratification of individuals presenting with MH; hence, reducing healthcare costs and patient discomfort. Petros Sountoulides: conceptualization, writing – review and editing, supervision. Georgios Langas: writing – original draft, investigation. Dimitrios Memmos: writing – original draft, investigation. The authors declare no conflicts of interest.