Preliminary Findings from the Finnish ProScreen Trial: A Three-Phase Screening Protocol for Improved Prostate Cancer Detection

Core Concepts

A new three-phase screening protocol incorporating PSA test, four-kallikrein panel, and MRI scan can improve prostate cancer detection rates compared to no screening.

Abstract

The study presents preliminary findings from the Finnish ProScreen randomized clinical trial, which assessed a three-phase screening protocol for prostate cancer detection. The protocol involves:

Initial PSA test
Four-kallikrein panel for those with PSA ≥ 3.0 ng/mL to identify high-grade prostate cancer
MRI scan for those with a high kallikrein panel risk score (≥ 7.5%), followed by targeted biopsies

The study randomized 60,745 men aged 50-63 years, with 15,201 invited to the screening protocol and 45,544 in the control group.
Among the 7,744 men who agreed to screening (51% of the invited group):

209 (2.7%) underwent targeted biopsies
136 biopsies (65%) detected cancer, including 32 low-grade and 128 high-grade prostate cancers
Compared to the control group, the screening protocol led to the detection of:

1 additional low-grade prostate cancer per 909 men invited
1 additional high-grade prostate cancer per 196 men invited
The authors note these results are descriptive and should be interpreted provisionally, pending the trial's primary outcomes on prostate cancer mortality.

Stats

Among the 7,744 men who agreed to screening, 209 (2.7%) underwent targeted biopsies, and 136 biopsies (65%) detected cancer.
Compared to the control group, the screening protocol led to the detection of 1 additional low-grade prostate cancer per 909 men invited and 1 additional high-grade prostate cancer per 196 men invited.

Quotes

"Among the 7744 invited men who agreed to the three-phase screening protocol (51%), ultimately 209 (2.7% of all screened participants) had a targeted transrectal prostate biopsy. Overall, 136 of the biopsies (65%) detected cancer — 32 low-grade and 128 high-grade prostate cancers, for cumulative incidence rates of 0.41% and 1.65%, respectively."
"Compared with the control group, the intervention led to the detection of one additional low-grade prostate cancer per 909 men invited to screen and one additional high-grade prostate cancer per 196 men invited."

Key Insights Distilled From

New Screening Protocol May Improve Prostate Cancer Detection

by Sharon Worce... at www.medscape.com 04-19-2024

https://www.medscape.com/viewarticle/new-screening-protocol-may-improve-prostate-cancer-detection-2024a10007m5

Deeper Inquiries

How do the prostate cancer mortality rates compare between the screening and control groups in the ProScreen trial?

In the ProScreen trial, the prostate cancer mortality rates were not the primary outcome measured. However, the study did show that among the invited screening group, there were 39 low-grade and 172 high-grade prostate cancers detected. In comparison, the control group, which was not invited for screening, had 65 low-grade and 282 high-grade prostate cancers identified. The risk difference between the invited screening group and the control group was 0.11% for low-grade disease and 0.51% for high-grade disease. This suggests that the screening protocol led to the detection of additional high-grade prostate cancers compared to the control group.

What are the potential harms and risks associated with the three-phase screening protocol, and how do they compare to the benefits?

While the three-phase screening protocol used in the ProScreen trial showed promising results in detecting prostate cancers, there are potential harms and risks associated with this approach. One of the risks is overdiagnosis, where low-grade prostate cancers that may not cause harm are detected, leading to unnecessary treatments and psychological distress for patients. Additionally, there is a risk of false positives, which can result in unnecessary biopsies and procedures. The use of MRI scans in the protocol may also lead to incidental findings that require further evaluation.
However, the benefits of the screening protocol include the detection of high-grade prostate cancers that are clinically significant and may benefit from early intervention. By incorporating multiple screening modalities, the protocol aims to reduce unnecessary diagnoses of low-grade cancers while still capturing relevant cases. The potential benefits include a higher detection rate of high-grade cancers and a more targeted approach to biopsy, which can improve patient outcomes.

What other screening approaches or biomarkers could be integrated into a comprehensive prostate cancer detection strategy, and how might they impact the performance of the ProScreen protocol?

In addition to the PSA test, four-kallikrein panel, and MRI scan used in the ProScreen protocol, there are other screening approaches and biomarkers that could be integrated to enhance prostate cancer detection. One potential biomarker is the Prostate Health Index (PHI), which combines different forms of PSA to improve the accuracy of prostate cancer detection. Incorporating PHI into the screening protocol could provide additional information to guide decision-making on further diagnostic tests.
Another approach is the use of genetic testing, such as testing for BRCA mutations, which are associated with an increased risk of prostate cancer. Integrating genetic testing into the screening strategy could help identify individuals at higher risk and tailor screening recommendations accordingly. Additionally, emerging biomarkers like circulating tumor cells or exosomal RNA could offer new insights into prostate cancer detection and prognosis.
By incorporating these additional screening approaches and biomarkers into the ProScreen protocol, the overall performance of the screening strategy may be enhanced. These complementary tests could improve the accuracy of detecting both low-grade and high-grade prostate cancers, leading to more personalized and effective management of the disease.