medwireNews: The CADMUS investigators report a “slightly lower” rate of detection of clinically significant prostate cancers with multiparametric ultrasound than multiparametric MRI, but a higher rate of referrals for biopsy.
“Given that multiparametric ultrasound might be more readily available and accessible in some health-care settings than multiparametric MRI, or useful for patients who cannot undergo MRI scans, multiparametric ultrasound should be considered for patients at risk of prostate cancer,” they write in The Lancet Oncology.
The study was conducted at seven UK hospitals and included 306 men at risk for prostate cancer on the basis of an elevated prostate-specific antigen level or abnormal digital rectal examination. All men underwent both multiparametric ultrasound and multiparametric MRI, and the 257 with a positive result on one or both of the tests had a targeted biopsy.
The proportion of participants with a positive result (defined as lesions with a Likert score ≥3) was 88.9% with multiparametric ultrasound and 77.8% with multiparametric MRI, equating to a between-group difference of 11.1%. The positive test agreement was 73.2%.
Any cancer was detected by biopsy in just over half (51.8%) of the 257 men to have the procedure, and 83 (32.3%) had clinically significant disease, defined as a Gleason score of at least 4+3 in any area or a maximum cancer core length of 6 mm or longer of any grade (PROMIS trial definition 1).
Multiparametric ultrasound detected clinically significant cancer as per this definition in 25.7% of the 257 men, while the rate of detection with multiparametric MRI was 30.0%, giving a difference between the groups of –4.3%. The positive test agreement was 91.1%.
Hashim Ahmed, from Imperial College London in the UK, and co-researchers highlight that ultrasound picked up six clinically significant cancers missed by MRI, while MRI identified 17 that were missed by ultrasound. They add that a combined approach would have detected all 83 clinically significant cancers.
The team points out that the difference between multiparametric ultrasound and MRI “increased when using less stringent definitions of clinically significant cancer,” at –6.2% when using PROMIS definition 2 (any area with a Gleason score ≥3+4 or maximum cancer core length ≥4 mm of any grade) and –5.4% for cancers with a Gleason score of 3+4 or higher.
But “at all levels of clinical importance on biopsy, multiparametric ultrasound detected cancer not found by multiparametric MRI, meaning that a diagnostic strategy using both scans over multiparametric MRI alone will increase detection of clinically significant cancer,” continue Ahmed and colleagues.
Noting, however, that “this combined use will lead to an increased number of patients undergoing a prostate biopsy,” they conclude: “Further work will be needed on the acceptability to patients and physicians of a combined test approach, the use of additional risk factors, and cost-effectiveness.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2022 Springer Healthcare Ltd, part of the Springer Nature Group