Systematic review of the clinical effectiveness and cost-effectiveness of photodynamic diagnosis and urine biomarkers (FISH, ImmunoCyt, NMP22) and cytology for the detection and follow-up of bladder cancer

Abstract

Objective: To assess the clinical effectiveness and cost-effectiveness of photodynamic diagnosis (PDD) compared with white light cystoscopy (WLC), and urine biomarkers [fluorescence in situ hybridisation (FISH), ImmunoCyt, NMP22] and cytology for the detection and follow-up of bladder cancer.

Data sources: Major electronic databases including MEDLINE, MEDLINE In-Process, EMBASE, BIOSIS, Science Citation Index, Health Management Information Consortium and the Cochrane Controlled Trials Register were searched until April 2008.

Review methods: A systematic review of the literature was carried out according to standard methods. An economic model was constructed to assess the cost-effectiveness of alternative diagnostic and follow-up strategies for the diagnosis and management of patients with bladder cancer.

Results: In total, 27 studies reported PDD test performance. In pooled estimates [95% confidence interval (CI)] for patient-level analysis, PDD had higher sensitivity than WLC [92% (80% to 100%) versus 71% (49% to 93%)] but lower specificity [57% (36% to 79%) versus 72% (47% to 96%)]. Similar results were found for biopsy-level analysis. The median sensitivities (range) of PDD and WLC for detecting lower risk, less aggressive tumours were similar for patient-level detection [92% (20% to 95%) versus 95% (8% to 100%)], but sensitivity was higher for PDD than for WLC for biopsy-level detection [96% (88% to 100%) versus 88% (74% to 100%)]. For more aggressive, higher-risk tumours the median sensitivity of PDD for both patient-level [89% (6% to 100%)] and biopsy-level [99% (54% to 100%)] detection was higher than those of WLC [56% (0% to 100%) and 67% (0% to 100%) respectively]. Four RCTs comparing PDD with WLC reported effectiveness outcomes. PDD use at transurethral resection of bladder tumour resulted in fewer residual tumours at check cystoscopy [relative risk, RR, 0.37 (95% CI 0.20 to 0.69)] and longer recurrence-free survival [RR 1.37 (95% CI 1.18 to 1.59)] compared with WLC. In 71 studies reporting the performance of biomarkers and cytology in detecting bladder cancer, sensitivity (95% CI) was highest for ImmunoCyt [84% (77% to 91%)] and lowest for cytology [44% (38% to 51%)], whereas specificity was highest for cytology [96% (94% to 98%)] and lowest for ImmunoCyt [75% (68% to 83%)]. In the cost-effectiveness analysis the most effective strategy in terms of true positive cases (44) and life-years (11.66) [flexible cystoscopy (CSC) and ImmunoCyt followed by PDD in initial diagnosis and CSC followed by WLC in follow-up] had an incremental cost per life-year of over 270,000 pounds. The least effective strategy [cytology followed by WLC in initial diagnosis (average cost over 20 years 1403 pounds, average life expectancy 11.59)] was most likely to be considered cost-effective when society's willingness to pay was less than 20,000 pounds per life-year. No strategy was cost-effective more than 50% of the time, but four of the eight strategies in the probabilistic sensitivity analysis (three involving a biomarker or PDD) were each associated with a 20% chance of being considered cost-effective. In sensitivity analyses the results were most sensitive to the pretest probability of disease (5% in the base case).

Conclusions: The advantages of PDD's higher sensitivity in detecting bladder cancer have to be weighed against the disadvantages of a higher false-positive rate. Taking into account the assumptions made in the model, strategies involving biomarkers and/or PDD provide additional benefits at a cost that society might be willing to pay. Strategies replacing WLC with PDD provide more life-years but it is unclear whether they are worth the extra cost.