Early-stage breast cancer includes stage I, IIA, and IIB.
Locally-advanced breast cancer includes stage IIIA, IIIB, and IIIC.
Metastatic breast cancer is stage IV.
Is StageIIIB considered early or borderline on advanced.
Just want to clarify that metastatic breast cancer is stage IV based on the TNM staging (any tumor size, with or without regional lymph node involvement, with presence of distant metastasis). A stage IIIB would mean T4N0-2M0.
You are currently on tamoxifen. This is one of the systemic hormonal treatments in breast cancer. One of the side effects of tamoxifen is endometrial cancer. Since you already had a hysterectomy, you are not an increased risk anymore of developing endometrial cancer.
As for your question on ovarian cancer, there is a risk if you have BRCA1 or BRCA2 mutation carrier. According to several studies published the lifetime risk of developing ovarian cancer for BRCA1 mutation carrier 16-63%, while that of BRCA2 mutation carrier is 10-27%.