Category: Prostate Cancer Imaging

HM-MRI Beats mpMRI

Posted on by Jake Fishman

University of Chicago researchers provided solid evidence that hybrid multidimensional MRI (HM-MRI) might be superior to multiparametric MRI (mpMRI) for diagnosing clinically significant prostate cancer.

That’s a big statement after nearly two decades of prostate MRI exams, but mpMRI’s continued variability challenges still leave room for improvement, and some believe HM-MRI’s quantitative approach could help add objectivity.

To test that theory, the researchers had four radiologists with different career experience (1 to 20yrs) interpret HM-MRI and mpMRI exams from 61 men with biopsy-confirmed prostate cancer, finding that the HM-MRI exams produced:

  • Higher AUCs among three of the four readers (0.61 vs. 0.66; 0.71 vs. 0.60; 0.59 vs. 0.50; 0.64 vs. 0.46), with the least experienced rad achieving the greatest AUC improvement 
  • Higher specificity among all four readers (48% vs. 37%; 78% vs. 26%; 48% vs. 0%; 46% vs. 7%)
  • Significantly greater interobserver agreement rates (Cronbach alpha: 0.88 vs. 0.26; >0.60 indicates reliability)
  • Far shorter average interpretation times (73 vs. 254 seconds)

The Takeaway
As the study’s editorial put it, HM-MRI appears to be a “quantitative step in the right direction” for prostate MRI, and has the potential to address mpMRI’s variability, accuracy, and efficiency challenges.

A Case for Multiparametric Ultrasound

Posted on by Jake Fishman

A new Lancet study out of the UK provided the strongest evidence yet that multiparametric ultrasound might deserve a core role in prostate cancer screening, either as a complement or alternative to multiparametric MRI. That could be a big deal given mpMRI’s cost, time, and accessibility challenges, and makes this study worth a deeper look.

The Study – The researchers performed mpUS and mpMRI exams on 306 patients with signs of prostate cancer (either elevated PSAs or abnormal rectal exams), and then conducted targeted biopsies on the 257 patients who had positive imaging findings. 

The biopsy results revealed cancer in 133 patients, including 83 clinically significant cancers, while showing how mpUS might contribute to prostate cancer diagnosis:

  • mpUS was positive in 272 patients (89%)
  • mpMRI was positive in 238 patients (78%)
  • mpUS identified 66 clinically significant cases (79%)
  • mPMRI identified 77 clinically significant cases (93%)
  • mpMRI and mpUS combined to detect all 83 clinically significant cancers
  • mpUS exclusively detected 6 clinically significant cancers 
  • mpMRI exclusively detected 17 clinically significant cancers

In other words, mpUS was only slightly less accurate than mpMRI for clinically significant cancer detection (-4.3%), but led to far more biopsies (+11.1%), while the combined modalities notably improved clinically significant cancer detection (+7.2%). 

The Takeaway

mpMRI’s role in prostate cancer screening is still secure, but this study shows that mpUS could improve cancer detection if the modalities are used together. Perhaps more importantly, it suggests that mpUS could be a valid prostate cancer detection option for the half of the world that doesn’t have access to advanced imaging or for the many patients who can’t/won’t undergo MRI (orthopedic implants, claustrophobia etc.).

The PSMA PET/CT + mpMRI PCa Effect

Posted on by Jake Fishman

There’s been a growing number of studies comparing 68Ga-PSMA PET/CT and mpMRI’s effectiveness along the prostate cancer pathway, but new research suggests that the modalities might be particularly effective if used together early in the diagnostic process.

The Study – A team of Australian researchers reviewed pre-operative mpMRI and 68Ga-PSMA PET/CT exams from 1,123 men (median PSA = 6), comparing their imaging results and histology findings. Here’s what they discovered:

  • mpMRI identified tumors in 93 men (8%) that were missed by 68Ga-PSMA PET/CT
  • 68Ga-PSMA PET/CT spotted tumors in 117 men (10%) that mpMRI missed
  • The combined modalities identified index tumors with Gleason Scores of ≥3+4 in 92% of men (vs. 80% w/ only mpMRI & 82% w/ only PSMA PET/CT)
  • 68Ga-PSMA PET/CT and mpMRI performed similarly for lesion/tumor detection and localization

Better Assessments and Decisions – In addition to identifying more tumors, mpMRI and 68Ga-PSMA PET/CT’s combined localization accuracy might improve biopsy targeting, leading to more accurate tumor grading and better management decisions.

More Necessary Biopsies – Meanwhile, patients with negative mpMRI and 68Ga-PSMA PET/CT findings would likely have a low risk of clinically significant prostate cancer, making them solid candidates for active PSA monitoring and allowing them to avoid unnecessary biopsies.

The Takeaway – This approach needs a lot more research and PSMA tracers currently only have FDA approval for patients with metastatic prostate cancer or biochemical recurrence, so 68Ga-PSMA PET/CT won’t be combined with mpMRI in early diagnostic exams very soon. That said, this study suggests that we’ll see more future efforts to combine and evaluate mpMRI + 68Ga-PSMA PET/CT as an early diagnostic step.

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