Side effects

What are the side effects for a patient who doesn't take tamoxifin (tamoxifen) for the five years after breast cancer surgery (lumpectomy) and (radiation treatment); and is their risk greater of a recurrence than a patient who takes tamoxifin (tamoxifen)?

[Cleveland Clinic]

Dear JBA48, The reason for giving tamoxifen after surgery and/or radiation treatment of breast cancer is to try to prevent or minimize the growth of microscopic deposits of tumor cells that might grow into a recurrent tumor (adjuvant therapy).  Tamoxifen is an anti-estrogen treatment it blocks estrogen in certain tissues of the body particularly the breast. Antiestrogen treatments are frequently given following surgery for ER/PR-positive breast cancer to reduce the risk of recurrence in the form of metastatic disease.  

Decisions about giving anti-estrogen treatment are based on many factors, including size of tumor, status of lymph nodes, the appearance of the cancer under the microscope, the presence or absence of hormone receptors for estrogen and/or progesterone, the general health of the patient etc.  The discussion of risks and benefits for the individual patient would be best done between the patient and their surgeon or medical oncologist.