Kelly,
"Focally" is an adverb from the word focal and means, in terms of cancer, limited to a specific area.

"Invasive" a stage of cancer in which cells have spread to healthy tissue adjacent to the tumor.

Differentiate: In cancer, refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably.

Staging:

Stage III: The tumor is larger than 4 centimeters (about 1.5 inches) in size and may involve a single lymph node on the same side of the neck.


Stage IV: The cancer has spread to tissues around the lip and oral cavity (the lymph nodes in the area may contain cancer); the cancer is any size and has spread to more than one lymph node on the same side of the neck as the cancer, to lymph nodes on one or both sides of the neck, or to any lymph node that is larger than 6 centimeters (larger than 2 inches); or the cancer has spread to other parts of the body.

- Key word in staging definitions "may".

Here's a link to a dictionary of cancer terms:
http://www.cancer.gov/dictionary/

I sure hope you heard wrong because I had RT/ct only. Other advanced stage survivors here have had the same protocol and doing fine.