Prostatic pathology reporting in the UK: development of a national external quality assurance scheme

Aims:  To develop a baseline picture of prostatic pathology reporting in the UK, identify areas of particular difficulty and assess the feasibility of a national external quality assurance scheme based on prostatic biopsy specimens using the same format as the National Health Service breast pathology scheme, as recommended by the National Institute for Clinical Excellence.
Methods and results:  Eight expert uropathologists and 32 randomly selected pathologists participated in four circulations each of 12 cases of prostatic biopsy specimens. A fixed text proforma was developed and responses were analysed for interobserver agreement using κ statistics. Consistency of reporting the main diagnostic categories of benign and invasive carcinoma was good (κ values 0.77 and 0.88, respectively), but only after excluding 19% of cases for which the experts did not reach 75% agreement. Areas of difficulty included the diagnosis of high-grade prostatic intraepithelial neoplasia and small foci of cancer. Prognostic factor reporting was more variable, with lower overall κs for the assessment of Gleason grading (experts 0.55, others 0.50), perineural invasion (experts 0.64, others 0.50) and number of positive cores (experts 0.74, others 0.61).
Conclusions:  Given the difficulties in diagnosis of prostatic biopsy specimens and the assessment of prognostic factors, the expansion of the scheme could deliver important educational benefits.