Adequate histologic sectioning of prostate needle biopsies.

No standard method exists for sampling prostate needle biopsies, although most reports claim to embed 3 cores per block and obtain 3 slices from each block. This study was undertaken to determine the extent of histologic sectioning necessary for optimal examination of prostate biopsies. We prospectively compared the impact on cancer yield of submitting 1 biopsy core per cassette (biopsies from January 2010) with 3 cores per cassette (biopsies from August 2010) from a large national reference laboratory. Between 6 and 12 slices were obtained with the former 1-core method, resulting in 3 to 6 slices being placed on each of 2 slides; for the latter 3-core method, a limit of 6 slices was obtained, resulting in 3 slices being place on each of 2 slides. A total of 6708 sets of 12 to 18 core biopsies were studied, including 3509 biopsy sets from the 1-biopsy-core-per-cassette group (January 2010) and 3199 biopsy sets from the 3-biopsy-cores-percassette group (August 2010). The yield of diagnoses was classified as benign, atypical small acinar proliferation, high-grade prostatic intraepithelial neoplasia, and cancer and was similar with the 2 methods: 46.2%, 8.2%, 4.5%, and 41.1% and 46.7%, 6.3%, 4.4%, and 42.6%, respectively (P = .02). Submission of 1 core or 3 cores per cassette had no effect on the yield of atypical small acinar proliferation, prostatic intraepithelial neoplasia, or cancer in prostate needle biopsies. Consequently, we recommend submission of 3 cores per cassette to minimize labor and cost of processing.