EURURO Vol. 72 No. 3

459 476

Incorrect grading and staging on re-reviewwas in part due to
new identification of higher-grade or -stage elements, likely
in part from involvement of more unspecialized pathologists
in previous years. This may explain some of the higher
incidence of originally reported pT3a GS6, but differences on
re-review were also due to changes and updates in ISUP
guidelines which occurred in 2005, 2009, and 2014. Danne-
man et al recently demonstrated that a steady increase in
Gleason scores has occurred, particularly since the 2005 ISUP
consensus . It is thus our opinion that in hospitals where
pathologists with genitourinary specialization are not
available, repeat review for radical prostatectomy specimens
would be beneficial, particularly for GS6 pT3 disease given
how rarely this was identified in our study.
Overall, our results add to a growing body of literature
demonstrating that GS6 prostate cancer rarely extends or
spreads outside the prostate. Before the most recent ISUP
consensus in 2014, Miyamoto et al had also noted rare focal
EPE for GS6 In addition, Samaratunga et al also reported
no pT3b disease in RP in a cohort of 2079 patients, but
pathologic grading in this report was performed using an
older version of ISUP criteria . In contrast to our
findings, two recent reports did show very rare GS6 pT3b
disease, although in the study by Kristiansen et al it is not
clear if Gleason grading was similar to the most recent ISUP
modification, and in the paper by Kweldam et al GS6 was
assigned when Gleason pattern 4 was <5%, which were
assigned 3 + 4 = 7 in our study . Additional research
from other centers to assess the incidence or absence of true
GS6 in pT3a–b, pT4, or node-positive prostate cancers will
be necessary to confirm our findings.
5. Conclusions
Contemporary GS6 prostate cancer exhibits EPE extremely
rarely (0.28%), and in our study was never associated with
more-adverse features such as SVI or lymph-node metasta-
ses. The rarity of extraprostatic extension and absence of
seminal vesicle invasion in true GS6 prostate cancer will be
confirmed or challenged by future studies, and will bring
significant insights into the malignant potential of this
grade of prostate cancer.
Author contributions: Blake B. Anderson had full access to all the data in the
study and takes responsibility for the integrity of the data and the accuracy
of the data analysis.
Study concept and design: Anderson, Razmaria, Paner, Eggener.
Acquisition of data: Anderson, Oberlin, Razmaria, Choy, Zagaja, Shalhav,
Meeks, Yang, Paner, Eggener.
Analysis and interpretation of data: Anderson, Oberlin, Razmaria.
Drafting of the manuscript: Anderson, Oberlin.
Critical revision of the manuscript for important intellectual content:
Anderson, Oberlin, Razmaria, Choy, Zagaja, Shalhav, Meeks, Yang, Paner,
Eggener.
Statistical analysis: Anderson, Oberlin.
Obtaining funding: None.
Administrative, technical, or material support: Choy, Yang, Paner.
Supervision: Zagaja, Shalhav, Meeks, Yang, Paner, Eggener.
Other (specify): None.
Financial disclosures: Blake B. Anderson certifies that all conflicts of
interest, including specific financial interests and relationships and
affiliations relevant to the subject matter or materials discussed in the
manuscript (eg, employment/affiliation, grants or funding, consultan-
cies, honoraria, stock ownership or options, expert testimony, royalties,
or patents filed, received, or pending), are the following: None.
Funding/Support and role of the sponsor: None.
Acknowledgments: We thank Nick Manalo for his efforts in retrieving
percent embedding data from over 1100 pathology reports from the
University of Chicago.
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