Angela,
First of all, welcome to our family!!
I was also diagnosed with Stage IIIB because a lymph node opposite side of the tumor lit up on the pet. I had the same questions regarding surgery. My treatment was very successful and I thought surgery was a possibility. Here is what I was told:
Vanderbilt onc: stated that surgery was too risky because of the amount of scar tissue left from radiation. Scar tissue, he said, is like cement and hard to heal once it is cut. He also said that even though the nodes are still enlarged they could be dead.
My personal onc said basically the same thing. When it gets in your lymph system and surgery was not available to you at diagnosis, it usually isn't an option.
The plus to this is that if your mom is responding well to treatment then hopefully all of the cancer will be gone.
If she feels she needs a 2nd opinion, I would not hesitate to get one at a comprehensive cancer center. This way her case can go before the board of oncs. and they can agree on the situation.
Hope this helps and GOD BLESS!
Jamie