Predictors of Gleason score upgrading in patients with a biopsy diagnosis of grade group 1 prostate cancer.

Background/aim: Transrectal ultrasound-guided biopsy is the most commonly used method in the diagnostic pathway of prostatic adenocarcinoma. The Gleason score of the tumor is the critical tissue-based determinant of patient management after diagnosis, and the main approach for low risk patients with grade group (GG) 1 disease is active surveillance rather than definitive interventions. However, a fair proportion of these cases are upgraded following radical prostatectomy (RP), if performed. We aimed to investigate the significance of clinicopathological parameters including phosphatase and tensin homolog (PTEN) protein in the prediction of higher final grade at RP in patients with a biopsy diagnosis of GG1 prostatic carcinoma.

Materials and methods: Thirty-three patients who underwent robotic-assisted RP for grade GG1 disease at prostate biopsy were evaluated retrospectively. Their clinical, radiological, and pathological features were explored in addition to the final histological grade in RP. Upgrade was defined as any increase in Gleason score from the initial needle biopsy to pathological analysis of the entire surgical specimen. Expression of PTEN in prostate biopsy cores was evaluated through immunohistochemistry. Multivariate logistic regression was performed to detect independent predictors of tumor upgrading from biopsy to RP.

Results: The final RP pathology revealed upgrading in 16 patients (48.5%) to GG2 disease. The statistics showed that Prostate Imaging Reporting and Data System score (≤3 vs. 4-5) of the index lesion and the number of involved cores in systematic biopsies (≤2 vs. >2) were the only independent predictors of the presence of a higher grade at RP (p < 0.05). The rate of PTEN loss for upgrading and nonupgrading patients was 25% and 5.9%, respectively, without statistical significance (p = 0.175).

Conclusion: Multiparametric magnetic resonance imaging findings and number of tumor positive needle cores are useful parameters to apply for predicting higher grade disease in the RPs of patients with a GG1 tumor diagnosis after a prostate biopsy. Immunohistochemical PTEN analysis, on the other hand, does not provide significant information in this respect.