(UroToday.com) The 2024 European Association of Urology (EAU) annual meeting featured a plenary session highlighting risk adapted screening for prostate cancer in Europe and a presentation by Dr. Jonas Hugosson discussing the Gothenburg-2 trial assessing PSA + MRI + targeted biopsies only. Dr. Hugosson started by highlighting several dilemmas with PSA-based screening that were noted in the Gothenburg-1 trial, particularly that the incidence of prostate cancer in the screening group was 15% compared to 7.4% in the control group. Overall, 31% of men would have never been diagnosed with prostate cancer if not invited to PSA screening, despite 25% in the screening group not attending, and opportunistic PSA testing being widely adopted in the control group. Dr. Hugosson states that this high rate of over-diagnosis is the main obstacle to why population-based screening has not been recommended by healthcare authorities.
One of the main reasons for overdiagnosis is the use of systematic biopsies. Dr. Hugosson notes that systematic (blind) biopsies now and then hit small well differentiated tumors which 30-50% of men 50-74 years of age harbor in their prostate. However, he notes that very few of these small cancers grow into clinically significant cancers. The following figure depicts the rationale for MRI followed by targeted biopsies only:
The following is the algorithm for the Gothenburg-2 trial:
Randomization for Gothenburg-2 was started in 2015 and stopped in January 2021. Altogether, 38,775 men aged 50-60 were randomized to the screening group and 19,000 men to the control group. The main endpoint is the rate of clinically insignificant prostate cancer (ISUP grade 1) detection.
The results from the Gothenburg-2 trial were published in 2022 in the New England Journal of Medicine. Among the men invited to undergo screening, 17,980 (47%) participated in the trial. The median age was 56 years (range 50-61), 7% of men had an elevated PSA (>= 3 ng/mL), and 95% of men with an elevated PSA underwent an MRI. Overall, 61% of men in the reference group had an MRI, and 64% in the experimental group. A total of 66 of the 11,986 participants in the MRI targeted biopsy group (0.6%) received a diagnosis of clinically insignificant prostate cancer, as compared with 72 of 5994 participants (1.2%) in the systematic biopsy group, a difference of -0.7 percentage points (95% CI, -1.0 to -0.4; RR 0.46, 95% CI 0.33 to 0.64; p <0.001). The relative risk of clinically significant prostate cancer in the MRI targeted biopsy group as compared with the systematic biopsy group was 0.81 (95% CI, 0.60 to 1.1):
Dr. Hugosson’s conclusions after the first round of screening were that the avoidance of systematic biopsy in favor of MRI-directed targeted biopsy reduced the risk of overdiagnosis by half at the cost of delaying the detection of intermediate risk tumors in a small proportion of patients. But, is it safe to delay diagnosis in MRI negative men? Will some prostate cancers become incurable before they become visible at MRI or will those small cancers become visible at MRI in subsequent screening rounds and still be curable? Follow-up results from the Gothenburg-2 study are forthcoming with data until June 30, 2022, now analyzed with a median follow-up of 4 years from the first invitation. This analysis includes the rate and type of cancers detected at repeated screening, as well as detected as interval cancers comparing the reference group (PSA, MRI, systematic and possibly targeted biopsies) and the experimental group (PSA, MRI, and targeted biopsies only). This manuscript is submitted and data will hopefully soon be published.
Presented by: Professor Jonas Hugosson, MD, University of Gothenburg, Gothenburg, Sweden
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 European Association of Urology (EAU) annual congress, Paris, France, April 5th - April 8th, 2024
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