INTRODUCTION
Prostate adenocarcinoma is the most common cancer in men and the second cause of mortality after lung cancer (1). The fact that the tumor has different growth rates in different histopathological (HP) patterns and its mortality is relatively low reveal the importance of the HP examination in terms of treatment modalities.
The Gleason scoring system, which was first developed by Donald Gleason in 1966 and universally accepted in 1974, has been updated over the years, but is still valid today and is seen as the most valuable prognostic parameter of prostate cancer (2–4). In recent studies, it was found that the prognoses of scores such as 3+4 and 4+3, which have the same sum but a different order of pattern frequencies, have been found to be different and this system has been updated. The latest classification which was published by the World Health Organization (WHO) in 2016, includes a consensus approach between the WHO and The International Urological Pathology Association (ISUP) after a meeting which was held in 2014 (5,6). According to this consensus report, Gleason score (GS) 2-5 were not included in this staging due to the difficulty in diagnosis, tumors with a GS 3+3=6 were classified as Group Grade (GG) I, tumors with 3+4=7 as GG II, tumors with 4+3=7 are classified as GG III, tumors with 4+4=8, 3+5=8, and 5+3=8 as GG IV and GS 9-10 are classified as GG V (6–8).
In addition to the GS, the HP parameters that are thought to affect prognosis include extraprostatic extension (EPE), surgical margin positivity (SMP), perineural invasion (PNI), lymphovascular invasion (LVI), seminal vesicle invasion (SVI), presence of a high-grade tertiary pattern and high grade prostatic intraepithelial neoplasia (HGPIN). While some of these have proven prognostic effects, some of them remain to be controversial (9,10). Besides, studies are reporting that the presence of cribriform type glands in the Gleason pattern 4 group has a worse prognosis than other pattern 4 histological subtypes (11–14).
Prostate-specific antigen (PSA) values in blood are used to determine the biochemical recurrence (BCR) in the postoperative period and it is also important in evaluating treatment response (15,16). Patients with a high GS are likely to show recurrence, but these criteria have not been clearly defined (6,8).
Based on all these information and updates, we aimed to revise the HP findings of radical prostatectomy (RP) materials according to the WHO-ISUP 2016 classification, to determine the BCRs of these patients in the postoperative period, and try to establish a correlation between the recurrent patients and HP features, to compare the new classification with the old one and to investigate the effects of the evaluated HP features in terms of recurrence and prognosis.