@ramidimitri Welcome to Mayo Clinic Connect. This is a good place to get support for you and your wife as we have lots of experience to share here. We aren't medical professionals but we can share our own experiences and make suggestions on what to ask the doctors.

I was diagnosed with a less aggressive kind of uterine cancer than your wife. Mine was endometrioid adenocarcinoma, FIGO Grade 1, Stage 1a. I had a radical hysterectomy and no further treatment at the time. Two years later I had a recurrence and the recommendation was for radiation therapy. I had 25 external pelvic radiation treatments and 2 internal (brachytherapy vaginal) treatments. I did not have chemotherapy.

Many of us here have external and internal radiation and were not asked to choose between the two options. I'm wondering why your wife is asked to choose? My recurrence was found at the top of vaginal (the vaginal cuff) which is why the internal treatment was recommended along with the external treatment. My understanding is that internal vs. external is not a question of which is better but instead which is more effective for treatment.

Here is something to read about radiation therapy from Mayo Clinic:

Mayo Clinic: Radiation Therapy

-- https://www.mayoclinic.org/tests-procedures/radiation-therapy/about/pac-20385162

American Cancer Society: Radiation Therapy for Endometrial Cancer:

-- https://www.cancer.org/cancer/types/endometrial-cancer/treating/radiation.html

Let's wait and see what other members share about their experiences with radiation. May I ask where you and your wife live? Are you in the U.S. or Canada?

@ramidimitri I had a higher stage than your wife, but lymph nodes were clear and all genetic testing and bio markers were unremarkable. I was recommended to have chemo and external radiation, but when I sought a second opinion, chemo was not necessary but available to me if I chose. When I went to the radiologist that the onco surgeon referred me to, she did give me options and told me the standard pros and cons of each. The possible side effects (fecal and urinary incontinence, tailbone damage, etc etc) were out of the question for me, and being a "minimalist," I opted for the most minimal internal radiation. I am very comfortable with my decision, but I realize that many other people feel more comfortable with a "scorched earth" approach and they feel comfortable that they have done the maximum that is available.

@ramidimitri This may be of interest to you https://www.cancer.gov/news-events/cancer-currents-blog/2019/endometrial-cancer-chemotherapy-without-radiation
I have advanced endometrial cancer (stage 3C), which, according to the article, explains why I didn't receive radiation, just chemo. Also, I have already had my life-time's limit of pelvic radiation to get rid of anal cancer.
The radiation has had lasting effects on my vagina--stenosis--which makes it virtually impossible for doctors to give me an internal exam without knocking me out.
If your wife has a non-aggressive form of endometrial cancer, then you might want to consider radiation, again, according to the article.