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Prostate‐specific antigen (PSA) complexed to α1‐antichymotrypsin improves prostate cancer detection using total PSA in Japanese patients with total PSA levels of 2.0–4.0 ng/mL
Author(s) -
Kobayashi Takashi,
Kamoto Toshiyuki,
Nishizawa Koji,
Mitsumori Kenji,
Ogura Keiji,
Ide Yoshihiro
Publication year - 2005
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/j.1464-410x.2005.05396.x
Subject(s) - prostate cancer , medicine , urology , prostate specific antigen , receiver operating characteristic , prostate , biopsy , cancer , area under the curve , prostate biopsy , cancer detection , gynecology
OBJECTIVE To assess the utility of prostate‐specific antigen (PSA) complexed to α1‐antichymotrypsin (PSA‐ACT) in prostate cancer screening in Japanese men with a total PSA level of 2.0–4.0 ng/mL, as improving cancer detection in men with these total PSA levels is a challenge for clinical urologists. PATIENTS AND METHODS Total PSA and PSA‐ACT were prospectively assessed and prostate biopsy recommended for patients who met either of two thresholds, i.e. a total PSA of ≥ 2.0 ng/mL or a PSA‐ACT of ≥ 1.5 ng/mL. The diagnostic ability of total PSA and PSA‐ACT, and free‐to‐total PSA ratio and prostate volume‐adjusted density were evaluated by receiver operating characteristic (ROC) analysis. RESULTS Of 1003 men enrolled, 547 met the biopsy criteria and a biopsy was taken in 315 (57.6%) patients. The area under the ROC curve for PSA‐ACT (0.679) was significantly greater than that for total PSA (0.601, P = 0.04) and equivalent to that for the free‐to‐total ratio (0.686, P = 0.911) in 116 men, including 27 with cancer with total PSA levels of 2.0–4.0 ng/mL. PSA‐ACT was more specific than the free‐to‐total ratio at a sensitivity of 95% (36% vs 18%, P < 0.05). The best variable for discriminating between cancer and benign disease in men with PSA levels of 2.0–4.0 ng/mL was PSA‐ACT density (area under the curve 0.852) which provided 66% specificity at a sensitivity of 90%. CONCLUSIONS PSA‐ACT is better than total PSA and equivalent to the free‐to‐total ratio for detecting prostate cancer in men with PSA levels of 2.0–4.0 ng/mL, and is thus useful for reducing the number of unnecessary biopsies.