STANDARDIZED IN-VITRO MAPPING WITH MULTIPLE CORE BIOPSIES OF TOTAL PROSTATECTOMY SPECIMENS - LOCALIZATION AND PREDICTION OF TUMOR VOLUME AND GRADE

Objective To analyse the ability of systematic core biopsy mapping to provide prognostic information in patients with prostatic cancer. Mate rials and methods The prostates of 60 men with prostatic cancer, stage s T0d-T2, who had undergone total retropubic prostatectomy were studie d. The average age of the patients was 63 years (range 49-72). Ten cor e biopsies (1.2 x 35 mm) were taken from the fresh specimens according to a standardized procedure. The total prostatectomy specimens were s erially step-sectioned at 5 mm intervals and were assessed regarding t umour volume, grade and pT-stage. The World Health Organization (WHO) grade obtained in the mapping biopsies was compared with that in the o perative specimens. Undergrading (WHO) decreased substantially by mapp ing biopsies, but was still present with the Gleason system. Results T he volume of extracapsular tumours with extensively positive margins w as significantly larger than that of intracapsular tumours (P < 0.01). In addition, the fraction of cancer obtained in the biopsies from tum ours with grossly positive margins was significantly smaller than that observed in biopsies from pT2 tumours (P < 0.01). The cancer Volume c alculated from the result of the mapping correlated positively with th e tumour volume determined by planimetry (R=0.83). A weaker correlatio n was found when only the six dorsal mapping biopsies were taken into consideration (R=0.68), but the correlation increased to R=0.75 when t he six most significant biopsies were selected with the help of a corr elation matrix. Biopsies from the ventral part of the prostate were al so important, to obtain an accurate assessment of the tumour fraction within the whole gland. Conclusion Mapping of the prostate gland with multiple (six or more) core biopsies is necessary for preoperative ass essment of tumour volume, grade and pT stage; these are all of importa nce when assigning patients with clinically localized prostatic cancer to prognostic classes.