Tamoxifen for Breast Cancer & Side Effects
What is this drug?
Tamoxifen is a treatment for breast cancer in both men and women that works by blocking estrogen from stimulating breast tissue. That stimulation leads in part to roughly 2/3 of breast cancers, and so blocking it is quite important, and Tamoxifen is the most popular breast cancer medication for that reason.
We have genetic tests these days and – if your cancer is positive for estrogen receptors (ER) – Tamoxifen is quite an effective treatment. Additionally, it has important protective effects in women who are at high risk. That said, for post-menopausal women, a different class of medication called the aromatase inhibitors may be a more effective treatment for certain types of breast cancer.
One study showed that over five years of treatment with Tamoxifen, your risk of developing ER+ cancer dropped almost 70%. That said, it has almost no effect on cancers which don’t have the ER, so its final effect is to reduce your risk of breast cancer by 50%.
Quite good. Unfortunately, Tamoxifen is technically a SERM – a selective estrogen receptor modulator. While it blocks estrogen from stimulating your breast, it actually acts like estrogen in your bone and uterine areas.
That means that treatment for extended periods of time can highly increase your risk of uterine cancer. The exact numbers aren’t entirely clear, but they range from doubling the risk to quintupling it. In terms of absolute numbers, 2.3 out 1,000 women will develop uterine cancer over the course of treatment.
As such, preventative use of tamoxifen should be reserved for people at high risk. One guide describes that as having a 1% or greater chance of developing cancer over a year if you have a uterus, and .5% or greater if you don’t. Issues that put you at high risk include BRCA1 or P53 genetic mutations, or simply having had strange growth in your breast.
What are the side effects of Tamoxifen?
Hormonal: Women taking tamoxifen are at increased risk of birth defects. This is because the drug interferes with the body’s hypothalamic-pituitary system, which can interfere with the menstrual cycle. Hot flashes are a common side effect, as well as ovarian cysts.
Skeletal: On the plus side, tamoxifen has positive effects on bones. Treatment with it is associated with a slight reduction in risk for bone fractures. The effect is not as strong as typical treatments and should not be sought after for itself.
Heart: Treatment causes a slight reduction in LDL cholesterol, but does not effect HDL levels. This effect has not been shown to have any cardiovascular benefits, however.
Blood: Tamoxifen has similar blood clotting risks as typical estrogen therapy. That means that you are at a higher risk of developing a clot which lodges in your veins or lungs, causing deep venous thrombosis or a pulmonary embolism, respectively.
Eyes: Treatment is associated with a 60% increase of risk for cataracts.
since taking tamoxifen for the past 6 months, I find that my whole body aches, I think it is muscular, as I hurt all over but when I start to use the muscles the pain lessens, I have consulted my GP but he dissmisses it, it appears to be getting worse, I was wondering if anybody ese has the same trouble.
i hurt all over also. I have severe cramps in both my legs. I have been on tamoxifen for yr and 3 months
have groin pain for year and half…getting worse. Onocologist. dismissing pain as not from tamoxifen. At first thought is was a future hip replacement or cancer. But test & xrays proved wrong…thankfuly
Hi I have been taking Tamoxafin and I also ache all over and have felt sick most of the time I am now having a break from it and feel like a new person I know that I have to go back onto them The doctor has sugested that I take them at night before I go to bed.
Watch this space we will find out!
Hi
I’ve been on tamoxifen for 4 years. At night I get leg cramps so bad I could hardly stand it. I’ve found out, through a friend, that Tonic water or Selzter water helps alot. I drink just a little before bed and I don’t get the leg cramps.
Another thing that really bothers me about tamoxifen, is not being able to lose weight. I exercise at the gym an hour 3 to 4 times a week, eat 1,000 to 1,300 calories a day but lost only 6 pounds in 3 months.
What I eat is fruits and veggies and sometimes fish or turkey.
I’ll really be glad to be off of it in March of 2011.
I’ve taken Tamoxifen for about a year and I, too, have very painful cramps in my legs at night, awaking me from sleep. beginning with my foot, then ankle, then calf. The only way to stop it is to immediately stand up and put weight on the foot. It isn’t a potassium or magnesium deficiency. I’ve tried all the tricks, including the electrolyte drinks. So now I’ll try tonic or seltzer water. By the way, Femara and Aromasin were both impossible to take. Tamoxifen is “only” about half as bad. If I’m off of it for 2-3 days, I’m like a different person, and am hoping I can last for another 4 years or so.
I was on Arimidex for three months with increasing deep muscle pain and was switched to tamoxifin a year ago. After about 5 months, I began to have flu like symptoms-no energy-so tired even upon waking-my hair was all over the place- on clothes, the floor, the bed-Ithink I have lost at least 1/4 of my hair and so many of my veins have surfaced especially on my legs which burn and sting constantly. I asked my oncologist to give me a break and he agreed to take me off for 2 months.
Am about to start taking tamoxifen, have been putting it off, can’t say the comments above inspire me at all, i am still trying to find my body and its rhythms after finishing chemotherapy. Can anyone tell me how it has affected their periods and libido? I have had 6 weeks of bleeding since finishing chemo with a 5 day break. Is tamoxifen likely to make it worse or better?