A review of contemporary grading systems for prostate cancer has found that modernization of the Gleason grading system results in more accurate grading for radical prostatectomy than older systems.
However, it has complicated the comparison of data before and after the updating, the researchers report.
"The Gleason grading system is one of the most powerful predictors of outcome in prostate cancer," explain Fadi Brimo (Montreal General Hospital, Quebec, Canada) and colleagues. Because the nature of prostate cancer has changed dramatically since the original system was introduced, it has undergone several modifications.
The investigators therefore performed a comprehensive review to investigate the implementation and impact of the Gleason system as a predictive and prognostic tool in all available treatment modalities, and to compare the original and modified Gleason systems in major pathologic and clinical outcome data sets.
All Gleason grade-related studies in the past 3 years were reviewed. For studies before this date, the researchers used literature from various books and original articles on the topic.
As reported in European Urology, a better prognostication with the updated Gleason grading system for patients treated with modalities other than surgery can only be assumed at this time because there are limited and conflicting data on radiotherapy and no studies on other treatment modalities.
Using the modified grading system resulted in disease upgrading with more cancers assigned a Gleason score of 7 or more than in the past.
There was no difference in the rate of Gleason score upgrading on repeat biopsies when comparing patients with very-low-risk versus low-risk cancer categories.
Brimo and team note that using the modified Gleason scoring resulted in a more homogenous Gleason score 6, which they say has an excellent prognosis when the disease is organ confined. This also makes active surveillance safer in the current era compared with the older system, they add.
Overall, the researchers say that the Gleason score is still one of the most critical predictive components for men with adenocarcinoma of the prostate regardless of the therapy used.
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