Pathological grade in biochemical recurrence of prostate cancer after radiation therapy – preliminary data

Prostate cancer (PC) is the most common urological malignancy, and the incidence is 1286 new cases in 2017., in Latvia. Significant number of patients develop a biochemical recurrence (BCR), after primary radical treatment, (27%-53%)1. Prostate Specific antigen (PSA) values serve as the foundation for defining BCR, however additional information is needed to identify potentially dangerous disease recurrence. Our objective in this study was to identify the use of MRI-fusion biopsy for the evaluation of PC pathological grade in BCR after radiotherapy (RT). We analyzed first 15 patients with a BCR after RT in 2020. Mean age was 73 years. All patients had a localized disease with a mean PSA value at time of treatment 18,9 ng/ml (4,9-63,5 ng/ml). The primary biopsy Gleason score was 5-8 and ISUP grade 1-4. Additionally, 13 patients had received androgen deprivation therapy (ADT). Mean time to BCR was 61,2 month (31-90month). BCR was identified according to the ASTRO criteria. For these patients a multiparametric MRI was done and analyzed by the PI-RADS 2.0 system, followed by an MRI-fusion trans-perineal prostate biopsy. Mean number of cores were 12 (5-25). All together 11 patients had a positive biopsy of at least one core. Of those, 6 patients shoved an upgrading of the Gleason score. 2 patients had no change in Gleason score and one patient had a lower grade. For 2 patients atypical cancers were seen. During restaging for one patient bone metastasis was diagnosed, and another patient had lymph node metastasis additionally. For 5 patients the biopsy and imaging were negative despite BCR. Our preliminary data shows that the histological grade in BCR is variable and may differ from the primary disease, with a significant upgrading. MRI-fusion biopsies in BCR may aid in diagnosing relevant cancer recurrence and high-risk disease earlier. Further clinical studies are needed.