The diagnostic accuracy and cost-effectiveness of magnetic resonance spectroscopy and enhanced magnetic resonance imaging techniques in aiding the localisation of prostate abnormalities for biopsy: a systematic review and economic evaluation.

BACKGROUND: In the UK, prostate cancer (PC) is the most common cancer in men. A diagnosis can be confirmed only following a prostate biopsy. Many men find themselves with an elevated prostate-specific antigen (PSA) level and a negative biopsy. The best way to manage these men remains uncertain.
OBJECTIVES: To assess the diagnostic accuracy of magnetic resonance spectroscopy (MRS) and enhanced magnetic resonance imaging (MRI) techniques [dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DW-MRI)] and the clinical effectiveness and cost-effectiveness of strategies involving their use in aiding the localisation of prostate abnormalities for biopsy in patients with prior negative biopsy who remain clinically suspicious for harbouring malignancy. DATA SOURCES: Databases searched--MEDLINE (1946 to March 2012), MEDLINE In-Process & Other Non-Indexed Citations (March 2012), EMBASE (1980 to March 2012), Bioscience Information Service (BIOSIS; 1995 to March 2012), Science Citation Index (SCI; 1995 to March 2012), The Cochrane Library (Issue 3 2012), Database of Abstracts of Reviews of Effects (DARE; March 2012), Medion (March 2012) and Health Technology Assessment database (March 2012). REVIEW
METHODS: Types of studies: direct studies/randomised controlled trials reporting diagnostic outcomes. INDEX TESTS: MRS, DCE-MRI and DW-MRI. Comparators: T2-weighted magnetic resonance imaging (T2-MRI), transrectal ultrasound-guided biopsy (TRUS/Bx). Reference standard: histopathological assessment of biopsied tissue. A Markov model was developed to assess the cost-effectiveness of alternative MRS/MRI sequences to direct TRUS-guided biopsies compared with systematic extended-cores TRUS-guided biopsies. A health service provider perspective was adopted and the recommended 3.5% discount rate was applied to costs and outcomes.
RESULTS: A total of 51 studies were included. In pooled estimates, sensitivity [95% confidence interval (CI)] was highest for MRS (92%; 95% CI 86% to 95%). Specificity was highest for TRUS (imaging test) (81%; 95% CI 77% to 85%). Lifetime costs ranged from £3895 using systematic TRUS-guided biopsies to £4056 using findings on T2-MRI or DCE-MRI to direct biopsies (60-year-old cohort, cancer prevalence 24%). The base-case incremental cost-effectiveness ratio for T2-MRI was <£30,000 per QALY (all cohorts). Probabilistic sensitivity analysis showed high uncertainty surrounding the incremental cost-effectiveness of T2-MRI in moderate prevalence cohorts. The cost-effectiveness of MRS compared with T2-MRI and TRUS was sensitive to several key parameters. LIMITATIONS: Non-English-language studies were excluded. Few studies reported DCE-MRI/DW-MRI. The modelling was hampered by limited data on the relative diagnostic accuracy of alternative strategies, the natural history of cancer detected at repeat biopsy, and the impact of diagnosis and treatment on disease progression and health-related quality of life.
CONCLUSIONS: MRS had higher sensitivity and specificity than T2-MRI. Relative cost-effectiveness of alternative strategies was sensitive to key parameters/assumptions. Under certain circumstances T2-MRI may be cost-effective compared with systematic TRUS. If MRS and DW-MRI can be shown to have high sensitivity for detecting moderate/high-risk cancer, while negating patients with no cancer/low-risk disease to undergo biopsy, their use could represent a cost-effective approach to diagnosis. However, owing to the relative paucity of reliable data, further studies are required. In particular, prospective studies are required in men with suspected PC and elevated PSA levels but previously negative biopsy comparing the utility of the individual and combined components of a multiparametric magnetic resonance (MR) approach (MRS, DCE-MRI and DW-MRI) with both a MR-guided/-directed biopsy session and an extended 14-core TRUS-guided biopsy scheme against a reference standard of histopathological assessment of biopsied tissue obtained via saturation biopsy, template biopsy or prostatectomy specimens. STUDY REGISTRATION: PROSPERO number CRD42011001376. FUNDING: The National Institute for Health Research Health Technology Assessment programme.