Study reports initial data on 3-step prostate cancer screening protocol

A prostate cancer screening intervention consisting of a prostate-specific antigen (PSA) test, a 4-kallikrein panel risk score, and an MRI led to the detection of 1 additional high-grade prostate cancer per 196 men and 1 additional low-grade prostate cancer per 909 men vs a control group representing current screening practices, according to initial findings in the ProScreen trial (NCT03423303) published in JAMA.¹

Men enrolled in the trial were randomly assigned 1:3 to be invited to undergo screening (n = 15,201) or to not being invited to undergo screening (n = 45,544).

“We have previously demonstrated that PSA screening can decrease prostate cancer mortality to some extent. However, PSA screening produces so many unnecessary cancer diagnoses that the harms outweigh the benefits. The new results show that the 3-step method now used produces fewer insignificant cancer diagnoses than PSA screening,” said lead author Anssi Auvinen, MD, PhD, in a news release on the findings.² Auvinen isa professor of epidemiology at Tampere University in Finland.

In total, the study included 60,745 eligible men, of whom 15,201 were invited to undergo screening and 45,544 were not invited to undergo screening and were meant to represent the current screening practices. Of the men who were invited to undergo screening, 7744 men participated.

Across the entire cohort invited to undergo screening, 39 low-grade prostate cancers (cumulative incidence, 0.26%) were detected, consisting of 32 among the men who participated in screening (cumulative incidence, 0.41%) and 7 among the men who did not participate (cumulative incidence, 0.1%). Further, 172 high-grade prostate cancers (cumulative incidence, 1.13%) were detected in this cohort, including 128 among the men who participated in the screening protocol (cumulative incidence, 1.65%) and 44 among the men who did not participate (cumulative incidence, 0.6%).

In the group not invited to undergo screening, 65 low-grade prostate cancers (cumulative incidence, 0.14%) and 282 high-grade prostate cancers (cumulative incidence, 0.14%) were detected during a median follow-up of 3.2 years.

Between the group invited to undergo the screening protocol and the control group, the risk difference was 0.11% (95% CI, 0.03%-0.20%) for low-grade cancers and 0.51% (95% CI, 0.33%-0.70%) for high-grade cancers.

Overall, the trial was coordinated by investigators at Tampere University and the University of Helsinki. Those included in the study were 50 to 63 years of age. Men enrolled in the trial were randomly assigned 1:3 to be invited to undergo screening (n = 15,201) or to not being invited to undergo screening (n = 45,544).

Men who were invited to undergo screening first received a PSA test. Those with a PSA level of 3.0 ng/mL or higher underwent additional testing with a 4-kallikrein panel risk score. Those with a score of 7.5% or higher on the kallikrein panel went on to receive an MRI of the prostate. A targeted biopsy was conducted in men with abnormal findings on MRI.

However, the authors noted that the current findings from the study only represent the first round of screening.

They wrote,¹ “These preliminary findings should be interpreted cautiously, pending results of the study’s primary outcome of prostate cancer mortality.”

The trial remains ongoing to assess the ProScreen trial’s primary end point of prostate cancer mortality, which will be assessed at 10 and 15 years of follow-up.³

References

1. Auvinen A, Tammela TLJ, Mirtti T, et al. Prostate cancer screening with PSA, Kallikrein Panel, and MRI: The ProScreen Randomized Trial. JAMA. 2024:e243841. doi:10.1001/jama.2024.3841

2. A new screening protocol can detect aggressive prostate cancers more selectively. News release. Tampere University. April 6, 2024. Accessed April 11, 2024. https://www.tuni.fi/en/news/new-screening-protocol-can-detect-aggressive-prostate-cancers-more-selectively

3. A randomized trial of early detection of clinically significant prostate cancer (ProScreen) (ProScreen). ClinicalTrials.gov. Last updated December 9, 2022. Accessed April 11, 2024. https://clinicaltrials.gov/study/NCT03423303