Just another confirmation why it's best to ensure your biopsy will be a combined one
(MRI-identified targets+systematic biopsy) rather than a target-only one.WHY DOES MRI-TARGETED BIOPSY MISS CLINICALLY SIGNIFICANT CANCERS?
INTRODUCTION AND OBJECTIVE:Multiple studies demonstrate that MRI-targeted biopsy detects more clinically significant prostate cancer than systematic biopsy. However, some clinically significant cancers are detected by systematic biopsy only
. We performed a post-hoc analysis of cases where clinically significant cancers were detected by systematic biopsy that were not detected by MRI-targeted biopsy to ascertain the reasons that MRI-targeted biopsy misses clinically significant cancer.METHODS:
Patients were enrolled in a nationally-registered prospective clinical trial comparing cancer detection rates by MRI-targeted fusion biopsy and systematic 12-core biopsy. Patients with an elevated PSA, or abnormal digital rectal exam underwent prostate MRI and subsequent MRI-targeted and systematic biopsy in the same setting. The subset of patients with clinically significant (grade group (GG) ≥ 3) cancer found on systematic biopsy and GG≤2 cancer on MRI-targeted biopsy were classified as MRI-targeted biopsy misses. Retrospective analysis of MRIs and MRI-targeted biopsy real-time tracked screen captures determined the cause of MRI-targeted biopsy miss. Characteristics of patients with MRI-targeted biopsy misses were then compared to GG-matched patients whose clinically significant cancer was accurately detected by MRI-targeted biopsy.RESULTS:
Among the 2,103 patients that underwent combined MRI-targeted and systematic biopsies, 466 patients had GG≥3 disease, and 41 (8.8%) men were identified as MRI-targeted biopsy misses.
Most MRI-targeted biopsy misses were due to errors in targeting ( n=21, 51.2%)
, followed by MRI-invisible lesions (n=17, 40.5%)
, and MRI lesions missed by the radiologist (7.1%, n=3)
. Lesions missed by targeted-biopsy were located predominantly in the peripheral zone, right-sided, and posteriorly. On multivariable regression analysis, lower PI-RADS score (OR: 0.46, p<0.001) predicted having clinically significant cancer missed on MRI-targeted biopsy, while PSAD, prostate volume, and prior biopsy, were not independently associated.CONCLUSIONS:
Most MRI-targeted biopsy misses are due to errors in lesions targeting highlighting the importance of accurate co-registration when using software-based fusion platforms. MRI-invisible lesions which are un-targetable by MRI-targeted platforms contribute to missing clinically significant cancer. Finally, having a low PI-RADS score despite a high PSAD is suggestive of harboring an MRI-invisible lesion, and these patients may benefit from combined biopsy."
The 8.8% miss rate jives with a figure of >7% that I remember from another study.
My take on this: you are on the table, presenting your tush, all numbed up, and the biopsy wand you-know-where. Have a train to catch? Why not have your doc take cores from the zones without MRI-identified targets? We know that lesions start out microscopically, so it isn't unreasonable to think there may be some small ones the MRI couldn't see that might have a greater Gleason score than the G score(s) of your primary lesion(s). Do the extra cores increase your chances of infection with a traditional TRUS? Probably? Perhaps? But that 8.8% would scare me more. Now I see there are aiming/alignment errors and MRI-reading errors as well.
When Forum brothers say a "targeted biopsy" is planned, I'm uncertain whether the doc means target-only or combined.