新しい血液検査が高リスク前立腺がんの検出率を向上（New blood test detects more high-risk prostate cancer cases）

2026-06-24

2026-06-23 カロリンスカ研究所（KI）

スウェーデンのKarolinska Institutetを中心とする研究チームは、高リスク前立腺がんの検出精度を向上させる新しい血液検査法を開発した。従来のPSA（前立腺特異抗原）検査は広く利用されているものの、過剰診断や不要な生検につながることが課題とされている。新たな検査では、血液中の複数のタンパク質バイオマーカーをAI解析と組み合わせて評価し、臨床的に重要な高リスク前立腺がんをより高い精度で識別できることが示された。研究では大規模な患者データを用いて性能を検証した結果、従来のPSA検査単独と比較して高リスク症例の発見率が向上し、不要な追加検査や侵襲的な生検の削減につながる可能性が示された。研究者らは、この手法が前立腺がんスクリーニングの効率化と早期治療の促進に貢献すると期待している。今後はさらに大規模な臨床評価を進め、実際の医療現場への導入を目指すとしている。

＜関連情報＞

ストックホルム3－磁気共鳴画像法を用いた集団ベースの前立腺がんスクリーニング研究：2年間の追跡調査 Stockholm3–Magnetic Resonance Imaging Population-Based Prostate Cancer Screening Study: Two-Year Follow-up

Thorgerdur Palsdottir, PhD, Chiara Micoli, MSc, Martin Eklund, PhD, Henrik Grönberg, MD, PhD, Fredrik Jäderling, MD, PhD, Derya Tilki, MD, Daniel W. Lin, MD, Matthew R. Cooperberg, MD, MPH, Scott E. Eggener, MD, Kevin C. Oeffinger, MD, Tobias Nordström, MD, PhD, and Hari T. Vigneswaran, MD
Annals of Internal Medicine Published:23 June 2026
DOI:https://doi.org/10.7326/ANNALS-25-04753

Abstract

Background:

Prostate-specific antigen (PSA) testing to screen for prostate cancer is controversial. An alternative approach, Stockholm3, combines PSA, plasma protein biomarkers, polygenic risk, and clinical factors into a multivariable risk score.

Objective:

To compare detection of clinically significant prostate cancer (csPC) using PSA and Stockholm3 in a population-based screening with short-term follow-up.

Design:

Secondary analysis of the baseline round of the prospective STHLM3-MRI (Prostate Cancer Screening Using a Combination of Risk-Prediction, MRI, and Targeted Prostate Biopsies) randomized screening trial in men aged 50 to 74 years who had PSA and Stockholm3 screening. Men with abnormal screening tests (PSA ≥3 ng/mL or Stockholm3 ≥11) were randomly assigned (2:3) to systematic biopsy or magnetic resonance imaging with systematic and targeted biopsies for lesions with a Prostate Imaging Reporting and Data System score of 3 or greater. Cancer diagnosed within 2 years was identified through linkage to the Swedish National Cancer Register; cancer after a negative baseline test was classified as false negative. (ClinicalTrials.gov: NCT03377881)

Setting:

Stockholm region, Sweden, 2018 to 2020.

Participants:

Men aged 50 to 74 years who had PSA and Stockholm3 screening.

Intervention:

Prostate-specific antigen and Stockholm3 tests at baseline.

Measurements:

Clinically significant prostate cancer (grade group ≥2) within 2 years of baseline.

Results:

Among 12 670 men, 443 (3.5%) were diagnosed with csPC. Decision curve analysis showed higher net benefit for Stockholm3 versus PSA across a range of decision thresholds for biopsy, indicating fewer unnecessary biopsies and fewer missed csPC cases. Stockholm3 (≥11) had a false-negative rate of 10% (43 of 443) and a false-positive rate of 11% (1289 of 12 227), whereas PSA (≥3 ng/mL) had a false-negative rate of 26% (116 of 443) and a false-positive rate of 10% (1203 of 12 227). Correspondingly, sensitivity was 90% (95% CI, 87% to 93%) for Stockholm3 and 74% (CI, 69% to 78%) for PSA, with similar specificity (89% vs. 90%).

Limitations:

Participation was approximately 25% of invited men; follow-up was limited to 2 years; and the cohort was predominantly Swedish or European, which may limit generalizability.

Conclusion:

In this screening cohort with short-term follow-up, Stockholm3 provided greater clinical net benefit than PSA for detecting csPC, driven by fewer false-negative results, although follow-up was limited to 2 years.