Pre-diagnostic prescription patterns in bladder and renal cancer: a longitudinal linked data study

Background: Understanding pre-diagnostic prescribing activity could reveal windows during which more timely cancer investigation and detection may occur. Aim: To examine prescription patterns for common urological clinical features prior to renal and bladder cancer diagnoses. Design and setting: We performed a retrospective cohort study using electronic primary care and cancer registry data on patients with bladder and renal cancer diagnosed between April 2012–December 2015 in England. Method: We analysed primary care prescriptions up to 2 years pre-diagnosis for five groups of clinical features (irritative urological symptoms, obstructive symptoms, urinary tract infections, genital infections, atrophic vaginitis). Poisson regressions estimating the inflection point, from which the rate of prescriptions increased from baseline, were used to identify the start of diagnostic windows during which cancer could be detected. Results: 48,094 prescriptions for 5,322 patients were analysed. Inflection points for an increase in UTI prescriptions were identified 9 months pre-diagnosis for renal (CI:5.3–12.7) and bladder (CI:7.4–10.6) cancers. For bladder cancer, the change in UTI antibiotic prescription rates occurred four months earlier in women (11 months, CI:9.7–12.3) than men (7 months, CI:5.4–8.6). No inflection points were identified, and so no diagnostic windows could be defined, for other clinical features. Conclusion: Prescription rates for UTIs increased 9 months before bladder and renal cancer diagnosis, indicating that there is potential to expedite diagnosis of these cancers in patients presenting with features of UTI. The greatest opportunity for more timely diagnosis may be in women with bladder cancer, who experienced the earliest increase in UTI prescription rate