My mom is 84 and we don't think she could recover from a hysterectomy.

None of the options are easy on someone 84 years old. The alternatives are radiotherapy, chemotherapy, hormonal thearpy, and no treatment. The problem with radiotherapy and chemotherapy is that the treatments have to be done for weeks or months, and the side effects can be severe. The side effects of chemotherapy are probably much worse than a hysterectomy. Its a toss-up whether side effects of radiotherapy are better or worse than a hysterectomy. The advantage of a hysterectomy is that the trauma lasts only for a couple weeks. No treatment is a good option if the cancer is contained and slow-growing. Hormonal therapy could be a good alternative, but it might not be effective at your mom's age. The oncologist should be able to describe the advantages and disadvantages of these options.