MRI-targeted plus systematic biopsy reduces over- and under-treatment

This article was initially published on March 4, 2020. As prostate cancer, and particularly concern about optimal methods for obtaining biopsies, remains a significant interest among BreakingMED users, we are republishing it as part of our year-end retrospective series on clinical news of 2020.

Combining traditional prostate cancer biopsy — systematic biopsy — with MRI-targeted biopsy provided the most accurate results, pinpointing more clinically relevant cancers and correctly identifying low-risk lesions, researchers from the National Institutes of Health reported.

Michael Ahdoot, MD, of the Urologic Oncology Branch at the National Institutes of Health Clinical Center in Bethesda, Maryland, and colleagues, wrote that the results of the Trio Study, which they reported in The New England Journal of Medicine, “should reduce the risk of both overtreatment and undertreatment out of fear of misdiagnosis.”

The researchers noted that systematic biopsy requires 12-core samples and is associated with both grade misclassification and missed diagnoses, while MRI-targeted biopsy “requires 12 fewer biopsy cores and leads to 5% fewer diagnoses of clinically insignificant cancers.”

But in Trio Study, Ahdoot and colleagues found that “the omission of systematic biopsy would lead to missing 1.9% more grade group 3 cancers and 5.8% more grade group 2 cancers in our study population. More important, among the patients in whom prostate cancer is diagnosed, the use of MRI-targeted biopsy alone leads to high diagnostic uncertainty, since this method used in isolation is associated with a 30.9% rate of any upgrading of the cancer group and an 8.7% rate of upgrading the cancer to a clinically significant grade group on whole-mount histopathological analysis.”

The take-home message on biopsy technique, the Trio investigators concluded, is not either/or, but both.

The Trio Study was actually a substudy of a larger NIH clinical trial looking at the use of tracking devices during invasive procedures. The researchers enrolled 2,103 men who had MRI-visible prostate lesions to undergo both MRI-targeted and systematic biopsy.

Among the findings:

  • 1,312 men had cancer diagnosed using both biopsy methods.
  • 404 of those men underwent radical prostatectomy.
  • Fewer grade 1 cancers (P <0.001) were detected by MRI-targeted biopsy alone than by systematic biopsy.
  • Detection of grade 3 (P =0.004), grade 4 (P <0.001) and grade 5 cancers (P =0.003) was significantly higher with MRI-targeted biopsy.
  • “Combined biopsy led to cancer diagnoses in 208 more men (9.9%) than with either method alone and to upgrading to a higher grade group in 458 men (21.8%).”
  • If systematic biopsy were omitted, “8.8% of clinically significant cancers (grade group ≥3) would have been misclassified.”

The researchers noted that among “2,103 patients who underwent the two biopsy methods, prostate cancer was diagnosed in 1,104 patients (52.5%) with systematic biopsy alone and in 1,084 patients (51.5%) with MRI-targeted biopsy alone.”

Importantly, when MRI-targeted biopsy was added to systematic biopsy, 208 more cancers were diagnosed, 59 of which were clinically relevant disease. “The addition of MRI-targeted biopsy led to a reduction of 60 patients (from 454 to 394) who were classified as having clinically insignificant (grade group 1) cancer,” they wrote. “Specifically, 134 men in whom grade group 1 cancer was diagnosed on systematic biopsy were upgraded to grade group 2 or higher on MRI-targeted biopsy. Simultaneously, MRI-targeted biopsy led to 74 new grade group 1 cancer diagnoses among men in whom no cancer was detected on systematic biopsy, which led to a net reduction of 60 patients with a grade group 1 cancer diagnosis.”

Ahdoot and colleagues noted a number of limitations of their study, including the fact that it was conducted at a single institution where most of the practitioners are more experienced than those found in typical community settings. And, because the study focused only on patients with MRI-visible lesions, the findings may not be applicable to patients who have normal MRI findings.

The authors concluded that the findings “suggest that combined biopsy provides improved diagnostic accuracy over either systematic or MRI-targeted biopsy alone and better predicts the results of final histopathological analysis.”

Peggy Peck, Editor-in-Chief, BreakingMED™

Supported by the Intramural Research Program of the NIH, National Cancer Institute, Center for Cancer Research, NIH Clinical Center, and NIH Center for Interventional Oncology; by Philips, which provided materials and technical support as part of a Cooperative Research and Development Agreement; and by a research grant from the Dr. Mildred Scheel Foundation for Cancer Research.

Ahdoot had no financial disclosures.

Cat ID: 25

Topic ID: 78,25,730,25,192,73,925,480,481,96