prop70, you are welcome, and I hope that my input is helpful/supportive. See if this additional descript
ion helps to decipher the chart...
Your primary grade was Gleason 4. This represents the majority of the tumor pattern, and must be more than 50%. Your secondary grade was 5, which has to be less than 50% but more than 5%.
BUT, if your primary was only just over 50%, then your secondary was probably something closer to the complementary value of just under 50% because any possible tertiary values are typically small.
You may not know (from your pathology report) what % the primary & secondary patterns ended up being...they don't often include that level of detail. However, if you get the math I just described, you'll follow along that your combined % G4/5 pattern tumor is going to be high. (It has to be somewhere between the bare minimum of 55% and 100%...in the absence of better information, you may want to consider it to be around the average of these values.)
The chart's x-axis groups represent the combined % of G4/5 pattern tumor.
Here is the LINK to the medical study where this chart appeared (full pdf article, published in the Journal of Medical Oncology).
Hope this helps...