Role of the 4Kscore test as a predictor of reclassification in prostate cancer active surveillance

BACKGROUND

Management of active surveillance (AS) in low-risk prostate cancer (PCa) patients could be improved with new biomarkers, such as the 4Kscore test. We analyze its ability to predict tumor reclassification by upgrading at the confirmatory biopsy at 6 months.

METHODS

Observational, prospective, blinded, and non-randomized study, within the Spanish National Registry on AS (AEU/PIEM/2014/0001; NCT02865330) with 181 patients included after initial Bx and inclusion criteria: PSA ≤10 ng/mL, cT1c-T2a, Grade group 1, ≤2 cores, and ≤5 mm/50% length core involved. Central pathological review of initial and confirmatory Bx was performed on all biopsy specimens. Plasma was collected 6 months after initial Bx and just before confirmatory Bx to determine 4Kscore result. In order to predict reclassification defined as Grade group ≥2, we analyzed 4Kscore, percent free to total (%f/t) PSA ratio, prostate volume, PSA density, family history, body mass index, initial Bx, total cores, initial Bx positive cores, initial Bx % of positive cores, initial Bx maximum cancer core length and initial Bx cancer % involvement. Wilcoxon rank-sum test, non-parametric trend test or Fisher's exact test, as appropriate established differences between groups of reclassification.

RESULTS

A total of 137 patients met inclusion criteria. Eighteen patients (13.1%) were reclassified at confirmatory Bx. The %f/t PSA ratio and 4Kscore showed differences between the groups of reclassification (Yes/No). Using 7.5% as cutoff for the 4Kscore, we found a sensitivity of 89% and a specificity of 29%, with no reclassifications to Grade group 3 for patients with 4Kscore below 7.5% and 2 (6%) missed Grade group 2 reclassified patients. Using this threshold value there is a biopsy reduction of 27%. Additionally, 4Kscore was also associated with changes in tumor volume.

CONCLUSIONS

Our preliminary findings suggest that the 4Kscore may be a useful tool in the decision-making process to perform a confirmatory Bx in active surveillance management.

The management of active surveillance in prostate cancer: validation of the Canary Prostate Active Surveillance Study risk calculator with the Spanish Urological Association Registry

The follow up of patients on active surveillance requires to repeat prostate biopsies. Predictive models that identify patients at low risk of progression or reclassification are essential to reduce the number of unnecessary biopsies. The aim of this study is to validate the Prostate Active Surveillance Study risk calculator (PASS-RC) in the multicentric Spanish Urological Association Registry of patients on active surveillance (AS), from common clinical practice.

Initial experience with abiraterone acetate in patients with castration-resistant prostate cancer

OBJECTIVE

To describe the results obtained in 25 males with metastatic castration-resistant prostate cancer (MCRPC) treated with abiraterone (AA). A comparative analysis of abiraterone effectiveness and safety between our results and data published in the literature was conducted.

MATERIAL AND METHOD

Bi-institutional prospective analysis of 25 consecutive patients with MCRPC undergoing treatment with abiraterone, with a mean follow-up 7.9 (3-15) months was carried out. Treatment effectiveness and safety analyses regarding baseline characteristics of patients (age, prior treatments, basal PSA, performance status, pain, metastasis) were conducted.

RESULTS

At 13.6 months of follow-up, the overall survival is 80% (CI 95%: 11.8-15.4). Clinical and radiological-free progression survival is 9.5 ± 1 months (CI 95%: 7.7-11.3) and biochemical response is 6.8 ± 1 months (CI 95%: 5-8.7). Only the treatment with chemotherapy impaired significantly the response time to AA [6.4 months for radiological-free progression survival (CI 95%: 4.2-8,6) and 4.3 months for biochemical-free progression survival (CI 95%: 2.6-6)]. The incidence of adverse drug events was 36%, all of them grade 1-2/4 and, in no case, suspension or reduction of the dose of AA was needed.

CONCLUSIONS

The treatment with AA has been effective in our series, with a tolerability considerably higher than what other studies published.