Tomoxifen is some kind of medicine. Someone please tell me how much of tomoxifen would cause uterine cancer?

I need an answer a.s.a.p please anyone thanks.

Tamoxifen has been shown to increase the risk of endometrial cancer in post-menopausal women who still have a uterus (who have not had a hysterectomy). The lining of the uterus is called the "endometrium." Tamoxifen stimulates the growth of endometrial cells. Over time, the risk of cancer cells developing in this lining is higher for women on tamoxifen.

If you have had breast cancer, you have an increased risk of endometrial cancer. Tamoxifen makes the risk of endometrial cancer a bit higher. The longer you take tamoxifen, the higher your risk of developing a tamoxifen-related endometrial cancer. (But the risk is still low, less than 1%, even if you take tamoxifen for 10 years.) If you are diagnosed with endometrial cancer within the first two years of taking tamoxifen, the cancer was most likely there before you started taking the drug.


Post-menopausal women who take tamoxifen and who have not had a hysterectomy (uterus removal) are at a higher risk of developing endometrial cancer than women who are not on tamoxifen. In the NSABP鈥檚 Breast Cancer Prevention Trial, endometrial cancer occurred 2.5 times more frequently in women who took tamoxifen compared to women who took a placebo (inactive pill).

However, the risk of endometrial cancer is still low among women on tamoxifen: approximately 2 out of 1000 women on tamoxifen will develop endometrial cancer.

Research suggests that long-term use of tamoxifen among post-menopausal women increases the chances of endometrial problems. According to a review of 106 studies that was published in the journal, Gynecologic Oncology, women who use tamoxifen on a long-term basis are more likely to develop endometrial cancer and endometrial sarcomas than women who have not used tamoxifen. However, the NSABP studies reviewing the incidence of endometrial cancer and tamoxifen use found that earlier, highly treatable endometrial cancers were detected in women on tamoxifen. While women who are diagnosed with early-stage endometrial cancer generally have good prognoses (expected outcomes), the prognosis for advanced endometrial cancer can be far worse.

Because of these findings, women on tamoxifen are encouraged to have yearly gynecological exams. Any abnormal bleeding or uterine pain should be reported to a physician immediately. Women considering tamoxifen are encouraged to have an endometrial sampling (removal of cells in the lining of the uterus for microscopic examination) to make sure there are no pre-existing uterine problems. Researchers are investigating whether women on tamoxifen should receive annual vaginal ultrasound exams to screen for endometrial thickening. However, early studies do not indicate a need for routine ultrasounds and/or endometrial biopsies unless there are specific symptoms such as vaginal bleeding or spotting.

Tamoxifen is used to lower estrogen levels as a preventative measure againt developing breast cancer (in women at high risk) and also to treat breast cancer. It must be prescribed by a physician. It does not cause uterine cancer. I have listed a web page below that you may read. If you or a family member or friend is on tamoxifen and unsure of anything about it, you need to call the doctor and get clear answers.