Patient-specific risk of undetected malignant disease after investigation for haematuria, based on a 4-year follow-up

What's known on the subject? and What does the study add? When a standardized set of investigations are applied in a 'one-stop' haematuria clinic setting, the detection rates of malignancy in a given population are predictable and have been defined. The detection rates are known to vary according to the extent of haematuria as well as the patient age and sex. The current study attempts to understand the 'true' incidence of disease in the investigated population by re-analysing the records of an early cohort of patients four years after their initial investigations. The actual risk of missing disease in higher-risk groups appears to be greater than previously documented. OBJECTIVES To estimate the diagnostic accuracy of a guidelines-based haematuria clinic protocol by measuring the incidence of undetected malignancy during a follow-up period. To estimate an individual's post-test risk of having undetected malignancy using the protocol likelihood ratio and the population prevalence of disease. METHODS Data were collected prospectively on a cohort of 4020 consecutive patients who were referred to a 'one-stop' haematuria clinic between 1998 and 2003. All patients had a plain radiograph taken and underwent ultrasonography and flexible cystoscopy as a part of 'first-line' investigation. Intravenous urography was performed where indicated after abnormal first-line tests or in patients with persistent haematuria where no abnormality had been detected. Records of the initial 687 participants from the first year of the study were reviewed 4 years after the original consultation. Missed diagnoses of urinary tract malignancy were recorded and sensitivities, likelihood ratios and the post-test probability of missing all disease and upper tract malignancy were calculated. RESULTS As previously reported, the overall prevalence of malignant disease was 12.1% (18.9% for macroscopic haematuria compared with 4.8% for microscopic haematuria). The records of the first year's cohort of patients (N = 687) were analysed 4 years after their original consultation and 10 potentially 'missed' tumours were identified. The sensitivity of the protocol was 90.9% for the detection of all urinary tract malignancy (95% CI, 82.4 to 95.5) and 71% for upper tract tumours alone (95% CI, 45.4-88.3). The latter improves to 78.6% (95% CI, 52.4-92.4) with the addition of further upper tract testing. The probability of missing malignant disease overall was 1.7% (95% CI, 0.95-3.04) but this rose sharply to > 4% for males over 60 with macroscopic haematuria. For those with non-visible haematuria, the percentage probability of missed malignant disease was less than 1%. CONCLUSIONS The haematuria clinic protocol described is robust but it is not infallible. The risk of missing malignant disease in the higher risk groups identified in the study is much greater than previous studies would suggest. If additional upper tract testing or interval follow-up were to be recommended, it could be rationally targeted at these groups, given the measurable risk shown here.