In a Swedish study (GÖTEBORG-2) reported in The New England Journal of Medicine, Hugosson et al found that magnetic resonance imaging (MRI)-targeted prostate biopsy was associated with a lower risk of overdiagnosis of clinically insignificant prostate cancer compared with MRI-targeted and systematic biopsy in patients with elevated prostate-specific antigen. However, the reduced risk of overdiagnosis was achieved at the cost of missing a small number of intermediate-risk cancers.
As stated by the investigators, “Screening for prostate cancer is burdened by a high rate of overdiagnosis. The most appropriate algorithm for population-based screening is unknown.”
In the trial, 37,887 patients aged 50 to 60 years were invited to participate in regular PSA screening. Participants with PSA ≥ 3 ng/mL underwent prostate MRI. One-third of participants were randomly assigned to undergo systematic biopsy in addition to MRI-targeted biopsy of suspicious lesions; the remaining participants were assigned to undergo MRI-targeted biopsy only. Invitation started in September 2015 and random assignment ended in January 2020. The primary outcome was clinically insignificant prostate cancer defined as a Gleason score of 3+3. The secondary outcome was clinically significant prostate cancer defined as a Gleason score of at least 3+4.
The avoidance of systematic biopsy in favor of MRI-directed targeted biopsy for screening and early detection in persons with elevated PSA levels reduced the risk of overdiagnosis by half, at the cost of delaying detection of intermediate-risk tumors in a small proportion of patients.— Hugosson et al
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Among the patients invited to undergo screening, 17,980 (47%) participated in the trial. A total of 66 (0.6%) of 11,986 participants in the MRI-targeted group vs 72 (1.2%) of 5,994 in the MRI-targeted and systemic biopsy group received a diagnosis of clinically insignificant prostate cancer (difference = −0.7 percentage points, 95% confidence interval [CI] = −1.0% to −0.4%; relative risk [RR] = 0.46, 95% CI = 0.33–0.64, P < .001).
Clinically significant cancer was detected in 110 participants (0.9%) in the MRI-targeted group vs 68 participants (1.1%) in the MRI-targeted and systemic biopsy group (RR = 0.81, 95% CI = 0.60–1.10). Clinically significant cancer was detected only by systemic biopsy in 10 patients in the latter group; all cases were classified as intermediate risk, primarily involving low-volume disease managed with active surveillance.
Mild adverse events (most commonly hematuria and hematospermia) were common in both groups. Outpatient antibiotic treatment for urinary tract infection within 30 days after biopsy was received by three participants (0.03%) in the MRI-guided group vs seven (0.1%) in the MRI-guided and systemic biopsy group. Hospitalization within 30 days occurred for one patient (0.008%; due to urosepsis) vs four patients (0.07%; due to urosepsis in two and pneumonia and acute hypertension in one each). No deaths occurred within 30 days.
The investigators concluded, “The avoidance of systematic biopsy in favor of MRI-directed targeted biopsy for screening and early detection in persons with elevated PSA levels reduced the risk of overdiagnosis by half, at the cost of delaying detection of intermediate-risk tumors in a small proportion of patients.”
Jonas Hugosson, MD, PhD, of the Department of Urology, Sahlgrenska University Hospital, Gothenburg, is the corresponding author for The New England Journal of Medicine article.
Disclosure: The study was funded by Karin and Christer Johansson’s Foundation, Swedish Cancer Society, and others. For full disclosures of the study authors, visit nejm.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.