9273 prostate cancer (PCa) diagnoses were registered in Poland in 2010. Analysis of epidemiological data indicates a gradual increase in PCa incidence and PCa-associated mortality in Poland over the last decades, with mortality climbing slower than incidence (fig. 1, 2). Prostate cancer is predominantly found in the peripheral zone (70%), particularly in the apex area. 10-15% of patients develop PCa in the transitional, and 15-20% in the central zone (fig. 3) (1-3). PCa is diagnosed based on the examination of biopsy specimens, typically transrectal ultrasound guided multiple-core biopsy performed with tru-cut needle (^TRUScoreBx). Finger-guided multi-core biopsy (FGcoreBx) or fine-needle aspiration multicore biopsy (FNABx) that is also a finger-guided type of biopsy are justified only in patients with clinically evident PCa that requires solely histo- or cytopathological verification, without the need to accurately determine features assessable in ^TRUScoreBx (4-7). The key element of PCA evaluation is malignancy assessment, i.e. its grading. The malignancy is defined with Gleason score (Gl.s.) developed by Donald Gleason (1920-2008), in common use since 1978 (8, 9). According to this system, PCa is associated with 5 Gleason patterns ranging from the least (1) to most malignant (5), differing mostly by their architecture, and to a lesser degree by the features of the cancerous cells (fig. 4) (6). When grading a tumour, the dominant (primary) pattern within a given tumour is identified, along with the next-most frequent (secondary) one, and both are assigned numerical grades. The sum of these two numbers (referred to as Gleason numbers) reflects the cancer’s global malignancy, and is known as Gleason sum or Gleason score (Gl.s.), e.g. Gl.s. 7 (Gl.n. 4 + Gl.n. 3) means that 4 is the predominant malignancy pattern, with 3 being the next-most common one, with a reverse sequence of numbers (3 + 4) being prognostically more favourable. Discrepancies in the malignancy scores identified on the basis of tissue core samples and surgical specimens (removed prostate) have already been widely researched (10), with numerous urological studies worldwide devoted to the accuracy of grading. Both intraobserver and interobserver variability have been determined to be of substantial significance here (11-13). Polish urological literature, however, has so far not included publications on this subject, except for studies by the author of this paper (14-17).

To compare prostate cancer grade after biopsy and radical prostatectomy.

Research material consisted of prospectively collected medical data for 212 consecutive patients who underwent radical prostatectomy (RP) at the Urology Department of CPME, diagnosed with prostate cancer (PCa) based on transrectal ultrasound-guided multiple-core biopsy (^TRUScoreBx). The tissue samples collected in prostate biopsy and the RP specimens were consecutively evaluated by the same experienced pathologist.

The most common malignancy identified by the urologic pathologist in ^TRUScoreBx (UP-1¹) was Gleason score 4 and 5 (46.7%). Malignancy grade identified as Gl.s. > 7 was found in 32 patients (15.2%). The scores most frequently identified in radical prostatectomy specimens were Gleason scores 7 (34.8%) and 5 (23.3%).

Malignancy scores based on tissue core evaluation and examination of RP specimens (UP-1¹) are shown in table 1. The data were tested with Stuart-Maxwell test of marginal homogeneity, showing the discrepancies between malignancy scores based on examination of multiple core biopsy (Gl.s.^Bx) samples and postoperative specimens (Gl.s.^RP) to be statistically significant (p < 0.0001), thus evidencing a significant lack of concordance to exist between the scores. Similarly, kappa coefficient calculated for these scores (κ = 0.20) showed a considerable discrepancy between the scores (with κ = 1.0 there is full concordance = 100%, whereas κ = 0.20 means that statistically there is concordance in one in five cases). Hence, concordance was determined for 34.3% of the scores, and a lack thereof for 65.7% (tab. 2).

The comparison of PCa scores identified by the urologic pathologist (UP-1¹) based on multiple core biopsies (Gl.s.^Bx) and on examination of RP specimens (Gl.s.^RP) has been collectively presented in table 3.