Longitudinal assessment of urinary PCA3 for predicting prostate cancer grade reclassification in favorable-risk men during active surveillance.

BACKGROUND: To assess the utility of urinary prostate cancer antigen 3 (PCA3) as both a one-time and longitudinal measure in men on active surveillance (AS). METHODS: The Johns Hopkins AS program monitors men with favorable-risk prostate cancer with serial PSA, digital rectal examination (DRE), prostate magnetic resonance imaging and prostate biopsy. Since 2007, post-DRE urinary specimens have also been routinely obtained. Men with multiple PCA3 measures obtained over ⩾3 years of monitoring were included. Utility of first PCA3 score (fPCA3), subsequent PCA3 (sPCA3) and change in PCA3 were assessed for prediction of Gleason grade reclassification (GR, Gleason score >6) during follow-up. RESULTS: In total, 260 men met study criteria. Median time from enrollment to fPCA3 was 2 years (interquartile range (IQR) 1-3) and from fPCA3 to sPCA3 was 5 years (IQR 4-6). During median follow-up of 6 years (IQR 5-8), 28 men (11%) underwent GR. Men with GR had higher median fPCA3 (48.0 vs 24.5, P=0.007) and sPCA3 (63.5 vs 36.0, P=0.002) than those without GR, while longitudinal change in PCA3 did not differ by GR status (log-normalized rate 0.07 vs 0.06, P=0.53). In a multivariable model including age, risk classification and PSA density, fPCA3 remained significantly associated with GR (log(fPCA3) odds ratio=1.77, P=0.04). CONCLUSIONS: PCA3 scores obtained during AS were higher in men who underwent GR, but the rate of change in PCA3 over time did not differ by GR status. PCA3 was a significant predictor of GR in a multivariable model including conventional risk factors, suggesting that PCA3 provides incremental prognostic information in the AS setting.

Intermediate and longer-term outcomes from a prospective active-surveillance program for favorable-risk prostate cancer. Tosoian JJ, Mamawala M, Epstein JI, Landis P, Wolf S, Trock BJ, Carter HB.J Clin Oncol. 2015 Oct 20;33(30):3379-85. [Epub 2015 Aug 31]. doi: 10.1200/JCO.2015.62.5764.

PURPOSE: To assess long-term outcomes of men with favorable-risk prostate cancer in a prospective, active surveillance program. METHODS: Curative intervention was recommended for disease reclassification to higher cancer grade or volume on prostate biopsy. Primary outcomes were overall, cancer-specific, and metastasis-free survival. Secondary outcomes were the cumulative incidence of reclassification and curative intervention. Factors associated with grade reclassification and curative intervention were evaluated in a Cox proportional hazards model. RESULTS: A total of 1,298 men (median age = 66y) with a median follow-up of 5 years (range: 0.01-18.00y) contributed 6,766 person-years of follow-up since 1995. Overall, cancer-specific, and metastasis-free survival rates were 93%, 99.9%, and 99.4%, respectively, at 10 years and 69%, 99.9%, and 99.4%, respectively, at 15 years. The cumulative incidence of grade reclassification was 26% at 10 years and was 31% at 15 years; cumulative incidence of curative intervention was 50% at 10 years and was 57% at 15 years. The median treatment-free survival was 8.5 years (range: 0.01-18y). Factors associated with grade reclassification were older age (hazard ratio [HR] = 1.03 for each additional year; 95% CI: 1.01-1.06), prostate-specific antigen density (HR = 1.21 per 0.1 unit increase; 95% CI: 1.12-1.46), and greater number of positive biopsy cores (HR = 1.47 for each additional positive core; 95% CI: 1.26-1.69). Factors associated with intervention were prostate-specific antigen density (HR = 1.38 per 0.1 unit increase; 95% CI: 1.22-1.56) and a greater number of positive biopsy cores (HR = 1.35 for one additional positive core; 95% CI: 1.19-1.53). CONCLUSION: Men with favorable-risk prostate cancer should be informed of the low likelihood of harm from their diagnosis and should be encouraged to consider surveillance rather than curative intervention.