Optimising the Diagnosis of Prostate Cancer in the Era of Multiparametric Magnetic Resonance Imaging: A Cost-effectiveness Analysis Based on the Prostate MR Imaging Study (PROMIS)

Abstract

Background: The current recommendation of using transrectal ultrasound-guided biopsy (TRUSB) to diagnose prostate cancer misses clinically significant (CS) cancers. More sensitive biopsies (eg, template prostate mapping biopsy [TPMB]) are too resource intensive for routine use, and there is little evidence on multiparametric magnetic resonance imaging (MPMRI).

Objective: To identify the most effective and cost-effective way of using these tests to detect CS prostate cancer.

Design, setting, and participants: Cost-effectiveness modelling of health outcomes and costs of men referred to secondary care with a suspicion of prostate cancer prior to any biopsy in the UK National Health Service using information from the diagnostic Prostate MR Imaging Study (PROMIS).

Intervention: Combinations of MPMRI, TRUSB, and TPMB, using different definitions and diagnostic cut-offs for CS cancer.

Outcome measurements and statistical analysis: Strategies that detect the most CS cancers given testing costs, and incremental cost-effectiveness ratios (ICERs) in quality-adjusted life years (QALYs) given long-term costs.

Results and limitations: The use of MPMRI first and then up to two MRI-targeted TRUSBs detects more CS cancers per pound spent than a strategy using TRUSB first (sensitivity = 0.95 [95% confidence interval {CI} 0.92-0.98] vs 0.91 [95% CI 0.86-0.94]) and is cost effective (ICER = £7,076 [€8350/QALY gained]). The limitations stem from the evidence base in the accuracy of MRI-targeted biopsy and the long-term outcomes of men with CS prostate cancer.

Conclusions: An MPMRI-first strategy is effective and cost effective for the diagnosis of CS prostate cancer. These findings are sensitive to the test costs, sensitivity of MRI-targeted TRUSB, and long-term outcomes of men with cancer, which warrant more empirical research. This analysis can inform the development of clinical guidelines.

Patient summary: We found that, under certain assumptions, the use of multiparametric magnetic resonance imaging first and then up to two transrectal ultrasound-guided biopsy is better than the current clinical standard and is good value for money.

Keywords: Cost-effectiveness analysis; Magnetic resonance imaging; Model-based analysis; Prostate biopsy; Prostate cancer.

Fig. 1

Schematic of decision tree. The diagram represents the decision tree used to predict the outcomes of the diagnostic strategies. The diagram shows only the general structure of the tree for diagnostic strategies composed of MPMRI and TRUSB; a similar tree was used for strategies including TPMB. In the model, men can have a sequence of up to three tests. The black lines represent the possible test classifications. The red lines with a question mark represent decisions. Different decisions constitute different sequences of tests and hence different strategies. The diagram highlights strategies M7 (left side) and T7 (right side). In M7, men receive MPMRI and are classified as having no suspicion of cancer (no cancer; NC), suspicion of non-CS cancer, or suspicion of CS cancer. Men with a suspicion of CS cancer receive an MRI-targeted TRUSB, and are classified as having no cancer (NC), non-CS cancer, and CS cancer. Men in whom CS cancer was not detected, but had a suspicion of CS cancer at the MPMRI, receive a second MRI-targeted biopsy. In T7, men receive a TRUSB, and are classified as having no cancer (NC), non-CS cancer, and CS cancer. Men in whom CS cancer was not detected receive an MPMRI, and are classified as having no suspicion of cancer (NC), suspicion of non-CS cancer, or suspicion of CS cancer. Men classified as having a suspicion of CS cancer based on MPMRI results receive a second TRUSB—this time MRI-targeted TRUSB since there is now information from the MPMRI. CS = clinically significant; MPMRI = multiparametric magnetic resonance imaging; TPMB = template mapping biopsy; TRUSB = transrectal ultrasound-guided biopsy.

Fig. 2

(A) Detection of CS cancers per pound spent in diagnosis. (B) Quality-adjusted life years (QALYs) per NHS spend. Each bubble represents one of the 383 diagnostic strategies evaluated; their size is directly related to the probability that the strategy is cost effective and therefore forms the frontier (ie, forms the red line). The red bubbles represent the 14 diagnostic strategies that form the frontier at expected values. This means that, on average, these are the best strategies per pound spent. The black bubbles represent the strategies that do not form the frontier at expected values, but that have some probability of being in the frontier given their distribution of costs and outcomes. The grey bubbles represent the strategies that do not form the efficiency frontier at any simulation. Given the distribution of parameter inputs, these strategies are never efficient or cost effective. CS = clinically significant; NHS = National Health Service.