oophorectomy vs hysterectomy?

- 33yrs
- Diagnosed two weeks ago
- pre-menopausal
- ductal carcinoma
- ER+, PR+, HER2-
- 4cm, likely 1 node but not biopsied
- hasn't begun treatments yet; will be starting 4 cycles of Taxol and then 4 of A/C, on a 2-week period soon but needs to have either oophorectomy or a hysterectomy first.

My friend was recently diagnosed with breast cancer, has tested positive for the BRCA-2 gene, which is rare and signifies an increased risk for invasive breast and ovarian cancer. Additionally, her doctor has found a 7cm mass on her ovary, which they can't conclusively decide if it's cancer or not.

Right now, she needs to decide between having an oophorectomy or a hysterectomy within the next couple of days.

She has the following questions:

What is difference between the two in terms of their effects, hormonally, or otherwise?

Does the uterus compensate hormonally after oophorectomy?

Are there different, additional side effects to hysterectomy?

The context is prophylactic removal of hormone-producing organs to reduce risk of breast cancer metastasis, or recurrence, or emergence of a second primary breast cancer.