Stockholm3 tests improve prostate cancer screening.

Abstract

The use of magnetic resonance imaging (MRI) as part of the prostate cancer screening paradigm has the potential to reduce prostate cancer overdiagnoses, according to researchers at the Karolinska Institutet in Sweden. Results from the STHLM3-MRI trial, published in The New England Journal of Medicine (NEJM) in July 2021, demonstrated a reduction in overdiagnosis by using MRI-targeted biopsy over traditional biopsy methods.1 A new complementary study published in The Lancet Oncology by the same research group indicates that by adding a new blood test (the Stockholm3) to current screening measures, the need for MRIs to be performed could be reduced by up to 33%. This could mean reduced detection of sometimes numerous, low-risk prostate tumors. In the NEJM study, lead author Dr. Tobias Nordström and his colleagues discuss the need to compare traditional screening methods, such as prostate-specific antigen (PSA) tests that may reduce mortality but can also lead to adverse outcomes for the prostate cancer population, with utilizing risk prediction via blood test in combination with MRI-based biopsy.2, 3 The Stockholm3 test analyzes a combination of several important diagnostic aspects of disease-risk, including genetic markers, clinical data, and protein markers, using an algorithm. The call to revise diagnostic strategy was studied through a randomized, open-label, prospective trial in Sweden. Participants, males between ages 50 and 74 years, were invited to participate in screening procedures through the mail. Of the 49,118 men studied, 12,750 were enrolled into the trial and provided blood specimens. Those participants identified as being in an elevated risk group (n = 2293) were randomized to either standard treatment or experimental interventions. “Compared with PSA of 3 ng/mL or higher, a Stockholm3 of 0.15 or higher provided identical sensitivity to detect clinically significant cancer, and led to fewer MRI procedures (545 vs 846; 0.64 [0.55-0.82]) and fewer biopsy procedures (311 vs 338; 0.92 [0.86-1.03]),” wrote the researchers. “Compared with screening using PSA and systematic biopsies, a Stockholm3 of 0.11 or higher combined with MRI-targeted and systematic biopsies was associated with higher detection of clinically significant cancers (227 [3.0%] men tested vs 106 [2.1%] men tested; RP 1.44 [95% CI, 1.15-1.81]), lower detection of low-grade cancers (50 [0.7%] vs 73 [1.4%]; 0.46 [0.32-0.66]), and led to fewer biopsy procedures.”3 Walter M. Stadler, MD, the Fred C. Buffett Professor of Medicine and Surgery; dean for clinical research in the biological sciences division; director of the genitourinary oncology program; and deputy director of the Comprehensive Cancer Center at the University of Chicago, focuses on the treatment of advanced prostate cancer in his oncology practice. He describes a close collaborative relationship with urologists, as they are often most engaged in screening methods. “More efficient screening is likely to have a significant impact on the number of patients with advanced cancer who we need to treat,” he says. “One major goal for screening studies is to identify tests and screening approaches that minimize invasive procedures and the detection of clinically insignificant disease without sacrificing, and ideally enhancing, the detection of potentially lethal cancer.” Research surrounding current screening paradigms has distinct benefits, according to Dr. Stadler. “Screening in general, and for prostate cancer specifically, can not only detect cancers that are likely to cause significant issues for patients in the future, but can also detect cancers that are unlikely to be clinically important,” he says. “These kind of diagnoses can lead to unnecessary invasive procedures including biopsy and even major surgery. For prostate cancer, for example, Gleason 6 disease will almost never have an impact on a patient, with the major clinical problem being the potential for missing a significant cancer in patients for whom screening and biopsy suggest only clinically unimportant Gleason 6 disease.” Dr. Stadler believes that the Stockholm3 blood test trial results are seminal. “This paper clearly demonstrates that the combination of the Stockholm3 and PSA blood test, with subsequent selective MR imaging and guided biopsy of suspicious areas, markedly decreases the number of biopsies that need to be performed without sacrificing and potentially enhancing the number of potentially lethal cancers diagnosed,” he says.