Current practice of diagnosis and reporting of prostate cancer on needle biopsy among genitourinary pathologists

Abstract

As there is a lack of hard data in the literature about many of the issues relating to diagnosing and reporting prostate cancer, we sought to survey current practices. A questionnaire was sent to 93 genitourinary pathologists with a response rate of 69%. Almost all respondents (95%) used formalin as fixative for needle biopsies. Unstained intervening sections were retained by 47%. Three levels of needle biopsies were used routinely by 63%. For verification of a diagnosis of cancer, high-molecular-weight cytokeratin was still the most commonly used immunohistochemical marker (91%), followed by p63 (58%) and alpha-methylacyl-CoA-racemase (50%). Features considered pathognomonic for cancer were glomeruloid bodies (58%), collagenous micronodules (64%), circumferential perineural invasion (84%), and growth in fat (36%). With none of these present, 39% required a minimum of 2 to 10 glands (median, 3) to diagnose cancer, whereas the others had no lower limit. A Gleason score was always given to even minute cancer foci by 86% and typically a Gleason score 6 was assigned (77%). Perineural invasion was mentioned by 86%. The extent of cancer on needle biopsies was quantified by all respondents with number of involved cores (80%) being the most commonly used measure. Linear extent was estimated by almost all, either as a percentage (80%) or millimeters of cancer length (41%) or both (22%). Measuring cancer from end to end or subtracting intervening benign tissue were almost equally common. For those general pathologists who would like to be in the mainstream of most urological pathologists, our survey data provide a guideline on how to diagnose and report prostate cancer.