Welcome @freebird40r.
You're asking great questions. @beestrong @bethlee @elizm @oilermama @trixie1313 @kathyomaha55 may be able to share more about their experience with statins and breast cancer.

Mayo Clinic offers a program to address heart problems associated with cancer treatment called cardio-oncology. The Cardio-Oncology Clinic (https://www.mayoclinic.org/departments-centers/cardio-oncology-clinic/overview/ovc-20442193) evaluates people prior to cancer treatment and patients who have experienced side effects due their treatment, and can help evaluate treatment when you have both cancer and heart conditions.
Do you have access to a similar cardio-oncology program?