While the Gleason score for evaluating how aggressive an individual's PCa cells are behaving was developed around 1966, in 2014 the Grade Group system was put forth under the auspices of the International Society of Urological Pathology.
A quick (3:30) Youtube comparison and summary of the two:
https://www.bing.com/videos/riverview/relatedvideo?q=prostate+cancer+grade+groups+&mid=ba5fa55199ce8af34f21ba5fa55199ce8af34f21&form=vire So for several years now this newer GG system has been in play and used by a number of doctors and institutions along with the established Gleason score system.
So is either system dominant and used as the mainline scoring system? (Of course Gleason has been around longer). Is the GG system considered a "secondary" or "afterthought" system? Will one eventually become dominant in the future, if it is not already?
In an effort to get answers to these questions, I asked COPILOT:
Q: are prostate cancer specialists actively using the Grade Groups system as much as or more than the traditional Gleason score system?
A: Yes, many urologists are using the Prostate Cancer Grade Groups system. This system, which is a modification of the traditional Gleason scoring system, was developed to provide a more accurate prognosis and guide for treatment decisions. It consists of five grade groups that correspond to the traditional Gleason scores:
Grade Group 1: Gleason score ≤6
Grade Group 2: Gleason score 3+4=7
Grade Group 3: Gleason score 4+3=7
Grade Group 4: Gleason score 8
Grade Group 5: Gleason scores 9-10(Boldfaces below are mine).
This GG system helps in better stratifying patients based on the aggressiveness of their cancer, which in turn aids in making more informed treatment decisions. While there isn’t a precise number available, the Prostate Cancer Grade Groups system is increasingly being adopted by urologists worldwide. This system is often used alongside the traditional Gleason score in pathology reports and patient consultations. Many institutions, including prominent ones like Johns Hopkins and Cedars-Sinai, have integrated the Grade Groups system into their practice. The transition is ongoing, with both systems being used concurrently in many cases. Over time, the Grade Groups system is expected to become more prevalent due to its ease of use and better prognostic accuracy.But then I asked COPILOT:
Q: do prostate cancer specialists prefer the Gleason system over the Grade Groups system?
A: Yes, urologists commonly use the Gleason grading system to evaluate prostate cancer. This system helps them determine the aggressiveness of the cancer by examining tissue samples under a microscope. The Gleason score ranges from 6 to 10, with higher scores indicating more aggressive cancer. In recent years, the International Society of Urological Pathology (ISUP) has introduced a simplified grading system that complements the Gleason system. This new system groups Gleason scores into five grade groups, which can help reduce overtreatment of less aggressive cancers.As noted in the COPILOT answer above, "... there isn’t a precise number" commonly available to describe the frequency of use of either system, although the reading I did suggested that Gleason is perhaps more commonly in use right now than GG, largely because it has been around longer, and people "are used to it."
Perhaps the best statement I found on this question of one-or-the-other-use is from the Johns Hopkins website page "Prostate Cancer Grading System" :
https://pathology.jhu.edu/urologic/prostate-cancer-grading-systemwhich states
"The new grading system, using the above terminology, has been accepted by the 2016 World Health Organization (WHO). To avoid confusion, it will be prudent to report the new grading system, in conjunction with the Gleason system, until it becomes widely accepted and practiced [i.e. Gleason score 3+3=6 (Grade Group 1)]."It also seemed from my reading that the above phrase " ... until it becomes widely accepted and practiced" may apply in general, that many are waiting to see if the GG system does come to be seen as catching on, in which case it will appear more in reporting venues than is currently being done.
So for now the reasonable course of action would seem to at least remain aware of the GG system, as most of us probably already are, and in particular noting whether its use seems to be increasing over time.
If that turns out to be the case, then we will already be in good shape if GG does turn out to be the dominant reporting system in the future.
We will already know it.