Hi...
Where oral cancer is concerned cause, and location play a role in treatment.

Often HPV tumors are treated with radiation and chemotherapy alone. If it involves the tonsil, then surgeons may remove it prior to treatment. HPV tumors respond very well to radiation and chemo alone.

NON HPV oral cancer is a dog of a different color. Gum, cheek, tongue, palate etc (it sounds to me like your mother's started out in her gum area and moved into her jaw)... are generally treated with surgery first. And sometimes a dr. will leave it at that. However, depending on size and involvement of the area and other factors they will suggest chemoradiation. (more and more this is becoming standard as oral cancer can be aggressive and spread quickly) So I was told by my rads dr. and surgical oncologist (ENT) post surgery and post biopsy that they wanted to give me radiation and chemo as it cuts the odds of recurrence in half as opposed just surgery.

There are no guarantees with anything. But where your mother is concerned if she is healthy enough (radiation is NO PICNIC - its far worse that just chemo and just surgery) the initial treatment of chemotherapy - to shrink the tumor, would likely be followed up with surgery, to remove the remaining cancer and possibly rebuild the affected area - then based on her staging and involvement, radiation should be offered after she has healed from surgery - this is normally 6 weeks but depends on how quickly she heals and what they have done for her surgically. Usually 6 weeks is the average. Her healing and immune system may be compromised due to her chemo, so it's important that she get good nutrition and regain her strength during this healing period.

Do look into rads. It's hard. Even for people who are have an "easy time of it" Pain management is very important, and being proactive. knowing what to expect, and educating yourself should help you both get through it if it is suggested.

take care