A New System for Grading Prostate Cancer?

In the 1960s, a pathologist named Donald Gleason and his colleagues at the Minneapolis VA Hospital developed a numerical system for ranking prostate cancer (PCa) aggressiveness on a scale from 1 to 5. The Gleason grade (or Gleason score) system named after him have been in use ever since as a way to understand how aggressive a patient’s PCa disease is, and planning treatment accordingly.

Now, 17 experts from Johns Hopkins, Memorial Sloan Kettering, U Pittsburgh, Cleveland Clinic, and Sweden’s Karolinska Institute propose a simplified 5-point system.[i] Their thinking is based on analyzing the records of more than 26,000 patients (20,845 had prostatectomy, 5501 had radiation).

When is a 7 not a 7?

The alternate system would have the advantage of simplicity. Today’s Gleason grade is not a true 5-point scale because it involves summing up two values. Which number comes first is based on the largest per cent of PCa seen in each positive needle sample. Thus, Gleason 3 + 4 = 7 is different from Gleason 4 + 3 = 7; the second sum is more dangerous because there is more Gleason 4 than 3. Even though the Gleason system is based on numbers 1 through 5, the actual scale used is this:

3 + 3 = 6 (lowest grade PCa)

3 + 4 = 7

4 + 3 = 7

4 + 4 = 8

4 + 5 = 9

5 + 4 = 9

5 + 5 = 10

It’s really a 7-point scale. The authors state, “The lowest score, assigned 6, may be misunderstood as a cancer in the middle of the grading scale, and 3+4=7 and 4+3=7 are often considered the same prognostic group.” (Note that any sum less than 6 is not used for planning treatment.) Confusing, right?

Why would a new system be better?

A true 5-point scale can offer the smallest number of grades with “more accurate grade stratification.” This simplifies treatment planning. According to the authors, if the lowest grade is 1 instead of 6 (3 + 3), the current tendency to overtreat low-risk PCa can be greatly reduced.

I like the 5-point scale, an idea similar to the PI-RADS scoring system radiologists use to interpret multiparametric MRI prostate scans. (See my blog at https://sperlingprostatecenter.com/pi-rads-score/ to learn more.) Given the tendency of the medical profession to change slowly and cautiously, I don’t foresee rapid wide-spread adoption of a new system. However, the authoritative institutions and experts behind this study should help their proposal gain the consideration it well deserves. I expect that there will be quite a buzz about it at next year’s annual American Urological Association meeting.

[i] Epstein JI, Zelefsky MJ, Sjoberg DD, Nelson JB et al. A Contemporary Prostate Cancer Grading System: A Validated Alternative to the Gleason Score. Eur Urol. 2015 Jul 9. pii: S0302-2838(15)00557-6. doi: 10.1016/j.eururo.2015.06.046. [Epub ahead of print]

This site uses cookies to analyze traffic and user behavior, protect your privacy, and provide you with the best user experience. Learn more.

How can we help?

Contact us to discuss your prostate health and plan your path to wellness.