Contemporary prognostic indicators for prostate cancer incorporating International Society of Urological Pathology recommendations

Lars Egevad, Brett Delahunt, Glen Kristiansen, Hemamali Samaratunga, Murali Varma

Prognostic assessment is a key element in the management of patients with prostate cancer as it informs both treatment, follow-up and outcome prediction. Tumour grade should be based upon the novel and evidence-based recommendations of the International Society of Urological Pathology (ISUP) Consensus Conference of 2014, with ISUP grades 1-5 being derived from 2005 ISUP modified Gleason grading, i.e., ISUP grade 1 (3 + 3 = 6), grade 2 (3 + 4 = 7), grade 3 (4 + 3 = 7), grade 4 (3 + 5 = 8, 5 + 3 = 8, 4 + 4 = 8), and grade 5 (4 + 5 = 9 5 + 4 = 9, 5 + 5 = 10). Reporting the percentage of pattern 4 present is somewhat controversial. It does appear to have value for cases of ISUP grade 2 tumours where only small volumes of pattern 4 tumour are present, as this may assist in determining if a patient is appropriate for active surveillance. It is currently recommended that pure intraductal carcinoma (IDCP) not be graded. Here we here propose that atypical intraductal proliferation, indeterminate for high-grade prostatic intraepithelial neoplasia (PIN) and IDCP, should be reported as atypical proliferation suspicious for IDCP (ASID) with a note that the lesion is non-diagnostic. Pathological staging is dependent on tumour spread with the key factors being tumour volume, tumour extent including extraprostatic extension (focal and established), as well as seminal vesicle and pelvic lymph node involvement. Perineural infiltration in needle biopsies and lymphovascular invasion are evolving parameters that should be included in the pathology report. The identification of prognostic biomarkers is in evolution although a variety of transcription signatures have been shown to have utility in outcome assessment. Other molecular markers showing promise as prognostic indicators are PTEN, androgen receptors, PARP and tumour promoter (GST-pi, RASSF1, PITX2) methylation.