Föreläsningar och seminarier OnkPat Friday Seminar: Carcinoma of the prostate: Current controversies

Värd: Lars Egevad, institutionen för onkologi-patologi.

Abstract

The Gleason grading system is the lynchpin for the prognostic assessment of prostate cancer. Established in 1966 and published in its final form in 1977, a number of modifications of the Gleason system have been proposed. The 2005 modifications, formulated by the International Society of Urological Pathology (ISUP) at an international consensus conference, resulted in a significant grade inflation [1] which, in turn, had a major impact on treatment recommendations. Further consensus recommendations following the meeting of the ISUP in 2014 led to the development of Grade Group system which was primarily proposed to assist patients to understand the nature of their disease. [2] Both the nomenclature and the grading recommendations based on grade groups have come in for recent criticism with the observation that the original Gleason system provides greater prognostic information than more recent modifications. [3]

Further controversy relates to the nature of intraductal carcinoma of the prostate, which was originally described as acinar carcinoma infiltrating prostatic ducts. While early Gleason grading studies did not differentiate between intraductal or stromal invasive carcinoma for grading purposes, recent recommendations are that the grade of intraductal carcinoma should not be included in the Gleason score. This has arisen from the suggestion that not all intraductal carcinoma is invasive and that some foci represent in situ tumours. [4, 5] This latter conclusion is based upon reports of three cases from the same institution and no further cases have been documented. A major problem with neglecting the grade of IDCP in a focus of prostatic carcinoma is that the intraductal carcinoma of the prostate is usually of higher grade and as a consequence it is likely cancers would be undergraded. [6] This could mean that high grade tumours would be treated conservatively rather than with potentially curative surgery.

[1] Gleason inflation 1998-2011: a registry study of 97,168 men.
Danneman D, Drevin L, Robinson D, Stattin P, Egevad L
BJU Int 2015 Feb;115(2):248-55

[2] The 2014 International Society of Urological Pathology (ISUP) Consensus Conference on Gleason Grading of Prostatic Carcinoma: Definition of Grading Patterns and Proposal for a New Grading System.
Epstein JI, Egevad L, Amin MB, Delahunt B, Srigley JR, Humphrey PA, 
Am J Surg Pathol 2016 Feb;40(2):244-52

[3] Gleason scores provide more accurate prognostic information than grade groups.
Egevad L, Micoli C, Delahunt B, Samaratunga H, Garmo H, Stattin P, Eklund M
Pathology 2025 Apr;57(3):293-296

[4] Intraductal carcinoma of the prostate is not a diagnostic entity.
Delahunt B, Egevad L, Samaratunga H, Srigley JR, Cheng L, Clouston D, Furusato B, Kench J, Leite KRM, MacLennan GT, Moch H, Pan CC, Ro J, Tsuzuki T, van der Kwast T, Wheeler T, Yaxley JW
Histopathology 2021 Jan;78(2):342-344

[5] Tracking the origin of metastatic prostate cancer.
Lindberg J, Kristiansen A, Wiklund P, Grönberg H, Egevad L
Eur Urol 2015 May;67(5):819-22

[6] Intraductal carcinoma of the prostate is an aggressive form of invasive carcinoma and should be graded.
Samaratunga H, Delahunt B, Egevad L, Srigley JR, Billis A, Bostwick DG, Camparo P, Cheng L, Clouston D, Denham J, Furusato B, Hartmann A, Jufe L, Kench J, Kenwright DN, Kristiansen G, Leite KRM, MacLennan GT, Merrimen J, Moch H, Oxley J, Pan CC, Paner G, Ro J, Sesterhenn IAM, Shanks J, Thunders M, Tsuzuki T, Wheeler T, Yaxley JW, Varma M
Pathology 2020 Feb;52(2):192-196