New Screening Protocol May Improve Prostate Cancer Detection

TOPLINE:

A new three-phase screening protocol that incorporates a PSA test, a four-kallikrein panel, and an MRI scan appears to improve the prostate cancer detection rate among men invited to participate in a single screening compared with those not invited, according to preliminary findings from the Finnish ProScreen randomized clinical trial.

METHODOLOGY:

• Prostate-specific antigen (PSA) screening is currently recommended for men in the United States starting at age 55. However, the test is controversial, in large part because it often detects prostate cancer that is not clinically relevant and may lead to overtreatment of men with low-grade disease.
• The current ProScreen trial assessed a screening intervention that aims to reduce unnecessary diagnoses of prostate cancer but still catch relevant cancers and reduce prostate cancer mortality.
• The researchers randomized 60,745 eligible men aged 50-63 years to be invited to a three-phase screening intervention (n = 15,201) or to be part of a control group that was not invited to screen (n = 45,544).
• The screening group who agreed to participate (n = 7744) first underwent a PSA test. Those with a PSA of ≥ 3.0 ng/mL then underwent a four-kallikrein panel to identify high-grade prostate cancer. Those with a kallikrein panel risk score of 7.5% or higher underwent an MRI of the prostate gland.
• Targeted biopsies were performed in those with abnormal prostate gland findings on MRI. Most patients with a negative MRI were not recommended for systematic biopsy unless they had a PSA density of ≥ 0.15 ng/mL.

TAKEAWAY:

• 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.
• Over a 3.2-year median follow-up among the 7457 invited men who refused screening, seven low-grade and 44 high-grade prostate cancers were detected (cumulative incidence rates, 0.1% and 0.6%, respectively).
• Among the entire invited screening group, 39 low-grade (cumulative incidence, 0.26%) and 172 high-grade prostate cancers (cumulative incidence, 1.13%) were detected.
• Among men in the control group, 65 low-grade prostate cancers were ultimately identified and 282 high-grade. The risk difference between the invited screening group and control group was 0.11% for low-grade disease and 0.51% for high-grade disease. 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.

IN PRACTICE:

The three-phase screening approach used in this study detected additional cancers, compared with a control group not invited for screening, but “these results are descriptive and should be interpreted provisionally pending results from the trial on the primary outcomes of prostate cancer mortality,” the investigators said.