Post operative indication for tamoxifen thpy for welldiffern endomtr adeno ca ER+, PR+ no LN <1/2 myometr?

My wife is optd for above condition. total hysterectomy with bilat pelvic node resection done. no LN invovement. gynaecologist adivsed follow up. Oncophysician suggested tamoxifen therapy. I,m not sure as tamoxifen is known to incr endometrial cancer risk