PCA3 Materials & News

Tombal B, Andriole GL, Smets L, Stoevelaar H. Presented at the American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium, 2-4 February 2012, San Francisco, California, USA. Abstract no. 111

• This study, which applied systematically analysed expert recommendations for performing repeat prostate biopsies to the placebo cohort of the REDUCE (REduction by DUtasteride of prostate cancer Events) study, shows that the PCA3 Assay can reduce the number of repeat biopsies while maintaining the sensitivity to detect high-grade prostate cancer (PCa)

• In a previous study, using the RAND/UCLA appropriateness method (RAM), 12 European urologists established recommendations for the appropriateness of biopsy based on PSA, DRE, number of prior negative biopsies, prostate volume and life expectancy, with and without consideration of the PCA3 Score¹

• In this study, the appropriateness of repeat biopsy in the REDUCE placebo cohort², consisting of 1024 patients, was assessed for 3 scenarios

  • application of the RAM expert recommendations without consideration of the PCA3 Score (“RAM without PCA3”)

  • repeat biopsy considered inappropriate in men with a PCA3 Score < 20 (“PCA3 only”)

  • application of the RAM expert recommendations with consideration of the PCA3 Score (“RAM with PCA3”)

• There was a strong relationship between the RAM expert recommendations and the actual repeat biopsy outcome in the REDUCE placebo cohort. Of the men for whom a repeat biopsy was considered inappropriate by the RAM recommendations with PCA3, 90% actually had a negative repeat biopsy

• According to the RAM recommendations, a repeat biopsy was inappropriate (or avoidable) in 26% of men when PCA3 was not taken into consideration. However, when the RAM recommendations took the PCA3 Score into account, a repeat biopsy was considered inappropriate in 64% of men

• In addition, only 1% of men (N=8), for whom a biopsy was considered inappropriate by the RAM recommendations with PCA3, had high-grade PCa (defined as a Gleason sum ≥ 7) (Table 1). 

• The application of the RAM recommendations with PCA3 resulted in a greater reduction in repeat biopsies (64%) than the scenario’s using RAM recommendations without PCA3 (26%) whereas few high-grade PCa would have been missed (N=8, vs 14, respectively; Table 1)

• The diagnostic accuracy of the 3 scenarios for assessing high-grade PCa was also assessed (Table 2). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the RAM expert recommendations with PCA3 were superior to the scenario without PCA3. It was concluded that RAM expert recommendations only, which reflect the physician’s best clinical judgement, are fairly ineffective for selecting patients needing a repeat biopsy because the reduction in repeat biopsy rate is moderate and a significant proportion of high-grade PCa is missed. Therefore, the optimal algorithm to select patients who need a repeat biopsy should include both the RAM expert recommendations and the PCA3 Score, because this offers the highest reduction in repeat biopsy rate while maintaining the sensitivity to detect high-grade PCa

1)    Tombal B, et al. Biopsy and treatment decisions in the initial management of prostate cancer and the role of PCA3; a systematic analysis of expert opinion. World J Urol 2011;doi:10.1007/s00345-011-0721-0
2)    Aubin SM, et al. PCA3 molecular urine test for predicting repeat prostate biopsy outcome in populations at risk: validation in the placebo arm of the dutasteride REDUCE trial. J Urol 2010;184:1947-52

*: number of men with high-grade or low-grade PCa for whom a biopsy was considered inappropriate and thus would have been missed if these scenarios had been applied in clinical practice;
a: expert recommendations; b: repeat Bx considered inappropriate in men with a PCA3 Score < 20;
N: number of patients; Bx: biopsy

 a: expert recommendations; b: repeat biopsy considered inappropriate in men with a PCA3 Score < 20
CI: confidence interval; NPV: negative predictive value; PPV: positive predictive value

More information: Congress abstract