High risk of under-grading and -staging in prostate cancer patients eligible for active surveillance.

Background: Active surveillance (AS) is increasingly offered to patients with low risk prostate cancer. The present study was conducted to evaluate the risk of tumor under-grading and -staging for AS eligibility. Moreover, we analyzed possible biomarkers for predicting more unfavorable final tumor histology.
Methods: 197 patients who underwent radical prostatectomy (RPE) but would have met the EAU (European Association of Urology) criteria for AS (PSA<10 ng/ml, biopsy GS ≤ 6, ≤ 2 cancer-positive biopsy cores with ≤ 50% of tumor in any core and clinical stage ≤ T2a) were included in the study. These AS inclusion parameters were correlated to the final histology of the RPE specimens. The impact of preoperative PSA level (low PSA ≤ 4 ng/ml vs. intermediate PSA of >4-10 ng/ml), PSA density (<15 vs. ≥ 15 ng/ml) and the number of positive biopsy cores (1 vs. 2 positive cores) on predicting upgrading and final adverse histology of the RPE specimens was analyzed in uni- and multivariate analyses. Moreover, clinical courses of undergraded patients were assessed.
Results: In our patient cohort 41.1% were found under-graded in the biopsy (final histology 40.1% GS7, 1% GS8). Preoperative PSA levels, PSA density or the number of positive cores were not predictive for worse final pathological findings including GS >6, extraprostatic extension and positive resection margin (R1) or correlated significantly with up-grading and/or extraprostatic extension in a multivariate model. Only R1 resections were predictable by combining intermediate PSA levels with two positive biopsy cores (p = 0.004). Sub-analyses showed that the number of biopsy cores (10 vs. 15 biopsy cores) had no influence on above mentioned results on predicting biopsy undergrading. Clinical courses of patients showed that 19.9% of patients had a biochemical relapse after RPE, among all of them were undergraded in the initial biopsy.
Conclusion: In summary, this study shows that a multitude of patients fulfilling the criteria for AS are under-diagnosed. The use of preoperative PSA levels, PSA density and the number of positive cores were not predictable for undergrading in the present patient collective.