Baseline and longitudinal plasma caveolin-1 level as a biomarker in active surveillance for early-stage prostate cancer

Objectives: To evaluate the role of caveolin-1 (Cav-1) as a predictor of disease reclassification (DR) in men with early prostate cancer undergoing active surveillance (AS). Patients and Methods: We analysed archived plasma samples prospectively collected from patients with early prostate cancer in a single-institution AS study. Of 825 patients enrolled, 542 had ≥1 year of follow-up. Baseline and longitudinal plasma Cav-1 levels were measured using an enzyme-linked immunosorbent assay. Tumour volume or Gleason grade increases were criteria for DR. Logistic regression analyses were used to assess associations between clinicopathological characteristics and reclassification risk. Results: In 542 patients, 480 (88.6%) had stage cT1c disease, 542 (100.0%) had a median prostate-specific antigen level of 4.1 ng/mL, and 531 (98.0%) had a median Cancer of the Prostate Risk Assessment score of 1. In all, 473 (87.3%) had a Gleason score of 3+3. After a median of 3.1 years of follow-up, disease was reclassified in 163 patients (30.1%). The mean baseline Cav-1 level was 2.2 ± 8.5 ng/mL and the median 0.2 ng/mL (range, 0–85.5 ng/mL). In univariate analysis, baseline Cav-1 was a significant predictor for risk of DR (odds ratio [OR] 1.82, 95% confidence interval [CI] 1.24–2.65; P = 0.002). In multivariate analysis, with adjustments for age, tumour length, group risk stratification and number of positive cores, reclassification risk associated with Cav-1 remained significant (OR 1.91, 95% CI 1.28–2.84; P = 0.001). Conclusion: Baseline plasma Cav-1 level was an independent predictor of disease classification. New methods for refining AS and intervention may result.