TAMOXIFEN

 

TAMOXIFENI thought it fitting that in the first month of this website we choose a drug – a simple pill that has saved thousands of lives yet is unfairly ostracized by the press and public.  Please join me in learning more about this very important treatment for breast cancer.

Tamoxifen is a member of a class of drugs called Select Estrogen Receptor Modulators (SERM).  It was originally approved in 1977 for the treatment of stage 4 breast cancer.  Since that time it has been approved for the treatment of early stage breast cancer – stages 1, 2,3 -following surgery and chemotherapy if it is necessary.  It is also used to decrease the development of breast cancer in high risk patients.  Frequently these medications are known as “hormonal therapy” but in fact they are anti-hormonal treatments.

Tamoxifen works by blocking the estrogen receptors in breast cancer cells both in the breast but also those that may have escaped to other parts of the body.  Remember if breast cancer cells deposit in your liver, it is not liver cancer but breast cancer in the liver and therefore treated as breast cancer.  Tamoxifen does not lower the amount of estrogen in your body as many think but acts at the breast cancer cell surface.  Only breast cancers which have hormone receptors – estrogen and progesterone on their surface will benefit from tamoxifen.  Any degree of hormone receptor positivity will have some benefit from tamoxifen.

Tamoxifen will work in pre, peri and post-menopausal patients, unlike the other class of anti-hormonal drugs called aromatase inhibitors which only work in post-menopausal patients.  If there is ever a doubt as to your menstrual status, it is safer to take tamoxifen until it is clarified.  Also, remember that not having a period does not mean you are post-menopausal.

Tamoxifen is not only used for hormone receptor positive invasive breast cancer of any type – stage 1, 2, 3, or 4 but also can be used in patients with duct cell carcinoma in-situ (DCIS).  DCIS has not invaded the breast tissue and sits on the breast duct.  It is referred to as stage 0 breast cancer.  If it is not surgically removed it will become invasive.  Following surgery (and radiation if needed), tamoxifen for 5 years decreases the risk of invasive breast cancer from 8% to 5% in patients with DCIS.  It lowers the risk of invasive cancer in the original breast as well as the opposite breast.  If a patient is estrogen receptor/progesterone receptor negative and/or underwent removal of both breasts (bilateral mastectomies) in treatment of their DCIS, it is unlikely they will benefit from tamoxifen.

Tamoxifen may also be used in patients who are at risk of development of breast cancer.  This is based on family history, number of prior breast biopsies, presence of atypical hyperplasia and menstrual/pregnancy history.

Side effects of tamoxifen remain a concern why many patients do not want to take this medicine.  It always amazes me that patients who undergo chemotherapy and lose their hair, have nausea, weakness, mouth sores etc say “I am not taking that drug, have you seen the side effects”.  Yes, there are side effects but they pale in comparison to chemotherapy.  I would say over 90% of patients have no problems with this drug.  I see more issues with the statin drugs people take for high cholesterol.  Side effects of tamoxifen include hot flashes, some vision changes, a slight increase risk of uterine cancer (let your doctor know if you have vaginal spotting with blood), a slight increased risk of blood clots ( no more than a birth control pill),  and a rare risk of elevated calcium levels.  Like any drug there will always be a long list of potential side effects but the benefits of this drug far out way the side effects for an invasive breast cancer.  Some beneficial side effects are improvement in bone density and cholesterol levels.  Tamoxifen acts as anti-estrogen against breast cancer but pro-estrogen on the bones, lipids, and uterus (that is why there is a slight increase risk of uterine cancer).

Tamoxifen is taken once each day, anytime of the day, with or without food at a dose of 20mg.  It follows chemotherapy if that is also recommended as part of your treatment.  It is normally taken for 5 years but at the December 2012, San Antonio Breast Conference Symposium (SABCS), results of the ATLAS study revealed an increase in survival of 2.8% by taking tamoxifen for 10 years.  There was an increase in the risk of uterine cancer in those taking tamoxifen for 10 years.  In my patients, I am determining on an individual basis who should take tamoxifen for 10 versus 5 years.  Many factors go into consideration such as the stage of the original breast cancer, patient preference, and potential side effects.

In my opinion, tamoxifen is just as important if not more important than chemotherapy in the treatment of breast cancer.  It is also for the most part very well tolerated. And cheap – did I mention that – in these days of pricey oncology drugs, this is indeed a miracle.  Please have an open mind when discussing tamoxifen with your doctor.  It is a must in pre/peri menopausal patients with an invasive breast cancer and no health issues that would prohibit its use.  It can also be considered in patients with duct cell carcinoma in-situ (DCIS).

As always, good luck – Dr. Chris.

Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris was born in Europe but has lived in the US for many years. He attended college both in Europe and the US and completed medical school at the University of Texas. Residency and fellowship in oncology was completed at Baylor. Read More...
Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris Charlton

Dr. Chris Charlton