Five year ago I was in San Antonio for The San Antonio Breast Cancer Symposium as a patient advocate. My paper was on the ATLAS Study put out by Avon. It was on whether there was a carry over effect from Tamoxifen, a drug used to block hormones in pre-menopausal women.
They have know found that those who took Tamoxifen for 10 yeas as adjuvant therapy for their estrogen receptor (ER) positive breast cancer had a reduced risk of recurrence and overall survival compared to patients who stopped after 5 years. This is appears promising to younger or premenstrual women.
(My opinion: I know a patient who accidentally stayed on it for ten years. She just kept renewing the prescription. She is a a friend of my aunts. She did develop some eye problems. Oh, it was cataracts but you can develop that from some kinds of chemo. She changed her whole diet to fruit and grains. Those individuals with a family history of strokes or gynecological cancers may not want to stay on this drug for that long. I am on Armidex for the 8th year. It is used for post menopausal women.The study has not yet come back on the long term effects. Blocking hormones is quite the topic. We have hormones in our body, environment, and what we ingest. Two thirds of breast cancer is hormonal drive and can be blocked by hormonal blocking drugs.)