Hi:

It looks like it is for staging breast cancer in those who were treated with neoadjuvant chemotherapy. Here is a link to the abstract:

http://oncology.jamanetwork.com/article.aspx?artic...

"Using 1% or higher as the cutoff for ER positivity, 5-year disease-specific survival estimates determined using the CPS+EG stage ranged from 52% to 98%, thereby validating our previous finding that the CPS+EG score facilitates more refined categorization into prognostic subgroups than clinical or final pathologic stage alone. The AIC value for this model was 3333.06, while for a model using 10% or higher as the cutoff for ER positivity, it was 3333.38, indicating that the model fits were nearly identical."

For all staging, the 8th Edition of the AJCC staging system is expected to be published in 2016, as noted here:

https://community.breastcancer.org/forum/73/topics...

BarredOwl