Changes in Gleason scores for prostate cancer: what should we expect from a measurement?
BACKGROUND
Men diagnosed with prostate cancer receive therapy based on various clinical characteristics, including the Gleason score, a measurement (range, 2-10) describing a tumor's histological appearance. An upward shift has occurred in the distribution of Gleason scores during the past decade; this change was influenced by reports suggesting that lower scores (range, 2-4) should not be assigned to biopsy specimens.


METHODS
We (1) compared Gleason scores from 1994-1995 and 2004-2005 at the same institution, (2) reviewed representative articles examining changes in Gleason scores during the last 2 decades, and (3) assessed the implications of a change in histological measurements.


RESULTS
Among men diagnosed with prostate cancer at VA Connecticut, Gleason scores 2 to 4 were reported for 11.4% (19/167) of specimens in 1994-1995 but only 0.4% (1/260) of specimens in 2004-2005; this difference persisted after adjusting for age, clinical stage, and prostate-specific antigen (P < 0.001). Similar results were evident in previous publications on this topic. A change in criteria for a clinical measurement may have unintended consequences, including problems of inconsistency across "time" and "place."


CONCLUSIONS
Recent shifts in Gleason scores have led to fewer patients being diagnosed with low-grade prostate cancer; this change can have adverse impacts in clinical care and research.
Department of Medicine, Yale University School of Medicine, New Haven, CT, USA.
Jorge
J
Ramos
Edward
E
Uchio
Mihaela
M
Aslan
John
J
Concato
D000230:Adenocarcinoma / Q000097:blood / Q000145:classification / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015588:Observer Variation; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000145:classification / Q000473:pathology*; D013997:Time Factors
D017430:Prostate-Specific Antigen