Predicting the risk of harboring high-grade disease for patients diagnosed with prostate cancer scored as Gleason ≤ 6 on biopsy cores

Abstract

Purpose: Biopsy and final pathological Gleason score (GS) are inconstantly correlated with each other. The aim of the current study was to develop and validate a predictive score to screen patients diagnosed with a biopsy GS ≤ 6 prostate cancer (PCa) at risk of GS upgrading.

Methods: Clinical and pathological data of 1,179 patients managed with radical prostatectomy for a biopsy GS ≤ 6, clinical stage ≤ T2b and preoperative PSA ≤ 20 ng/ml PCa were collected. The population study was randomly split into a development (n = 822) and a validation (n = 357) cohort. A prognostic score was established using the independent factors related to GS upgrading identified in multivariate analysis. The cutoff value derived from the area under the receiver operating characteristic curve of the score.

Results: After RP, the rate of GS upgrading was 56.7%. In multivariate analysis, length of cancer per core > 5 mm (OR 2.938; p < 0.001), PSA level > 15 ng/ml (OR 2.365; p = 0.01), age > 70 (OR 1.746; p = 0.016), number of biopsy cores > 12 (OR 0.696; p = 0.041) and prostate weight > 50 g (OR 0.656; CI; p < 0.007) were independent predictive factors of GS upgrading. A score ranged between -4 and 12 with a cutoff value of 2 was established. In the development cohort, the accuracy of predictive score was 63.7% and the positive predictive value was 71.2%. Results were confirmed in the validation cohort.

Conclusion: This predictive tool might be used to screen patients initially diagnosed with low-grade PCa but harboring occult high-grade disease.