Essential Updates in Grading, Morphotyping, Reporting, and Staging of Prostate Carcinoma for General Surgical Pathologists

Abstract

Context.— Within this decade, several important updates in prostate cancer have been presented through expert international consensus conferences and influential publications of tumor classification and staging. Objective.— To present key updates in prostate carcinoma. Data Sources.— The study comprised a review of literature and our experience from routine and consultation practices. Conclusions.— Grade groups, a compression of the Gleason system into clinically meaningful groups relevant in this era of active surveillance and multidisciplinary care management for prostate cancer, have been introduced. Refinements in the Gleason patterns notably result in the contemporarily defined Gleason score 6 cancers having a virtually indolent behavior. Grading of tertiary and minor higher-grade patterns in radical prostatectomy has been clarified. A new classification for prostatic neuroendocrine tumors has been promulgated, and intraductal, microcystic, and pleomorphic giant cell carcinomas have been officially recognized. Reporting the percentage of Gleason pattern 4 in Gleason score 7 cancers has been recommended, and data on the enhanced risk for worse prognosis of cribriform pattern are emerging. In reporting biopsies for active surveillance criteria–based protocols, we outline approaches in special situations, including variances in sampling or submission. The 8th American Joint Commission on Cancer TNM staging for prostate cancer has eliminated pT2 subcategorization and stresses the importance of nonanatomic factors in stage groupings and outcome prediction. As the clinical and pathology practices for prostate cancer continue to evolve, it is of utmost importance that surgical pathologists become fully aware of the new changes and challenges that impact their evaluation of prostatic specimens.

Whole-Slide Imaging Allows Pathologists to Work Remotely in Regions with Severe Logistical Constraints Due to Covid-19 Pandemic

“…In fact, it is well known that among general pathologists, not specialized in genitourinary histology, the distinction between Gleason 3 and Gleason 4 glands can be challenging. [ 13 ] As it became apparent that working remotely was not only feasible but also the only possible solution to the problems caused by the social distancing measures, this approach was chosen to guarantee the proper functioning of the service. Studying histological patterns on WSI was not new to us as it is common practice to follow online pathology courses for continuous medical education programs generally based on WSI.…”

Understanding the gleason grading system and its changes

“…Also, the concept of atypical cribriform lesions and adenosis has improved with the widespread use of immunohistochemistry. 6,10,14 The vital changes which occurred over the last few decades had led to enhanced understanding, refinements and rearrangement of the Gleason patterns and the better outcome. 14 The GGS still remains one of the most powerful prognostic factors in prostatic carcinoma.…”

“…This basically eliminates Gleason 1 pattern. 6,[12][13][14] Gleason score 3 or 4 on needle biopsies (comprising of grades 1+2, 2+1 and 2+2) has also been controversial. The ISUP consensus recommended that diagnosis of Gleason score 3 or 4 can be made rarely on needle biopsies from transition zone or apex and after consultation with experts.…”

“…13,21 The 2014 ISUP Gleason score and GGS were introduced to overcome the 2005 Gleason score pitfalls. 14,21,[23][24][25] There were few major conclusions made out of 2014 ISUP. Cribriform and glomeruloid glands (regardless of morphology) should be assigned a Gleason pattern 4.…”

“…21 The reporting of Gleason scores 2 to 5 has virtually disappeared from current clinical practice. 14,21 This new grading system more accurately reflects prostate cancer biology than the Gleason system. Grade group1 out of 5 better characterizes the tumor than reporting as Gleason score 6 out of 10 and has an excellent prognosis.…”