title: Length of prostate biopsies is not necessarily compromised by pooling multiple cores in one paraffin block: an observational study.
abstract: BACKGROUND
  Individually submitted prostatic needle biopsies are recommended by most guidelines because of their potential advantage in terms of core quality. However, unspecified bilateral biopsies are commonly submitted in many centers. The length of the core is the key quality indicator of prostate biopsies. Because there are few recent publications comparing the quality of 12 site-designated biopsies versus pooled biopsies, we compared the lengths of the biopsies obtained by both methods.
  
  
  METHODS
  The material was obtained from 471 consecutive subjects who underwent prostatic needle biopsy in the Tampere University Hospital district between January and June 2013. Biopsies from 344 subjects fulfilled the inclusion criteria. The total number of cores obtained was 4047. The core lengths were measured on microscope slides. Extraprostatic tissue was subtracted from the core length.
  
  
  RESULTS
  The aggregate lengths observed were 129.5 ± 21.8 mm (mean ± SD) for site-designated cores and 136.9 ± 26.4 mm for pooled cores (p = 0.09). The length of the core was 10.8 ± 1.8 mm for site-designated cores and 11.4 ± 2.2 mm for pooled cores (p = 0.87). The median length for pooled cores was 11 mm (range 5 mm - 18 mm). For individual site-designated cores, the median length was 11 mm (range 7 mm -15 mm). The core length was not correlated with the number of cores embedded into one paraffin block (r = 0.015). There was no significant difference in cancer detection rate (p = 0.62).
  
  
  CONCLUSIONS
  Our results suggest that unspecified bilateral biopsies do not automatically lead to reduced core length. We conclude that carefully embedded multiple (three to nine) cores per block may yield cores of equal quality in a more cost-efficient way and that current guidelines favoring individually submitted cores may be too strict.
authors: Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland ; Department of Cancer Biology, Institute of Biomedical Technology, University of Tampere, Tampere, Finland.
authors: Teemu T
authors: TT
authors: Tolonen
authors: Department of Cancer Biology, Institute of Biomedical Technology, University of Tampere, Tampere, Finland.
authors: Jorma
authors: J
authors: Isola
authors: Department of Surgery, Satakunta Hospital district, Pori, Finland ; Department of Urology, Tampere University Hospital, Tampere, Finland.
authors: Antti
authors: A
authors: Kaipia
authors: Department of Urology, Tampere University Hospital, Tampere, Finland.
authors: Jarno
authors: J
authors: Riikonen
authors: Department of Surgery, Satakunta Hospital district, Pori, Finland ; Department of Materials Science, Tampere University of Technology, Tampere, Finland.
authors: Laura
authors: L
authors: Koivusalo
authors: Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland.
authors: Sanna
authors: S
authors: Huovinen
authors: Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland.
authors: Marita
authors: M
authors: Laurila
authors: Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland.
authors: Sinikka
authors: S
authors: Porre
authors: Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland.
authors: Mika
authors: M
authors: Tirkkonen
authors: Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland.
authors: Paula
authors: P
authors: Kujala
keywords: Biopsy quality; Guidelines; Prostate cancer; Prostatic needle biopsies