Tamoxifen May Increase Risk of Rare and Aggressive Breast Cancer
A new study indicates that long-term use of the breast cancer drug Tamoxifen can increase the risk that women will develop a rare and aggressive form of aggressive breast cancer.
The study, published in the online August 25 edition of Cancer Research, finds that while short-term use of Tamoxifen has definite and clear benefits for women who have had breast cancer and are trying to avoid a recurrence, users who take the drug for extended periods of time are four times as likely to have breast cancer return.
Researchers said the drug’s estrogen-blocking effects are very useful in preventing common, less aggressive cancer from returning, but long-term Tamoxifen side effects could aid in the growth of rare and more aggressive cancers that thrive when estrogen levels are low.
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Learn MoreThe study looked at 1,100 women who had been treated for breast cancer. From that group, 369 developed new tumors. When the researchers compared those women to the women who had stayed in remission, they found that women who took Tamoxifen for more than five years were four times more likely to develop the new forms of breast cancer, as well as being 60% less likely to develop more common, estrogen-dependent, breast cancer.
Tamoxifen, also known by the brand names Nolvades, Istubal and Valodex, was developed by AstraZeneca 30 years ago, and is widely available in generic form. Originally used to treat early-stage breast cancer, it has been used for the last ten years to also reduce the risk of cancer in women who are considered to have an increased risk of developing breast cancer. The drug works by acting against the effects of estrogen in breast tissue, preventing estrogen receptor-positive cancer cells from bonding with estrogen, which they need to grow.
Researchers said that their results should not discourage women from using Tamoxifen. The increased risk of breast cancer only appeared after a period of about five years of use, and most doctors prescribe the drug for five years or less.
The study comes on the heels of another study earlier this year that found Tamoxifen problems related to the use of some popular antidepressants, like Zoloft, Paxil and Prozac. A Medco Health Solutions study, released in late May, found that antidepressants known as selective serotonin reuptake inhibitors (SSRIs) more than doubled the chances of a breast cancer recurrence when used with Tamoxifen.
About half a million women take Tamoxifen in the United States, and that study raises serious concerns that a large percentage may be negating its effectiveness unknowingly. Nearly 30% of breast cancer survivors taking Tamoxifen use some form of antidepressant to treat hot flashes, which are a common side effect of Tamoxifen.
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7 Comments
ArleneApril 18, 2021 at 6:04 am
Tamoxifen is a horrible drug. Took it after breast cancer treatments approximately 5 years. It later caused uterine cancer and 9 years after the uterine cancer, Tamoxifen caused a recurrence of breast cancer but even more aggressive.
RonaldJanuary 15, 2013 at 5:12 pm
My wife had two in surgeries in 2002 to remove precancerous cells from her left breast, not officially called cancer by her doctor, her doctor put her on tamoxifen for five years, She had many side effects during this time, she was just 4 months shy of 5 years when while on vacation feeling discomfort she returned home to visit her doctor on April 2nd, 2007 and they discovered her liver was enlarg[Show More]My wife had two in surgeries in 2002 to remove precancerous cells from her left breast, not officially called cancer by her doctor, her doctor put her on tamoxifen for five years, She had many side effects during this time, she was just 4 months shy of 5 years when while on vacation feeling discomfort she returned home to visit her doctor on April 2nd, 2007 and they discovered her liver was enlarged and full of tumors. A few days later she was diagnosed with liver cancer, She began her first Chemotherapy treatment within the next few weeks, six days later she went into a coma on April 30th, 2007 and passed away a few hours later on the morning of May 1st, 2007 exactly one week after her treatment, I am left with four high school teenagers to raise on my own, the doctors told me that her cancer was not from the breast and yet her autopsy report says it was directly connected to her breast cancer.
JeannetteMarch 4, 2011 at 8:55 pm
I am 73, have taken Tamoxifen for 14 months, & now I have Deafness from Tamoxifen. I am getting my hearing aids next week. I stopped taking the pill 13 days ago, but I was told the nerve damage is permanent!
LaurieMay 4, 2010 at 6:33 am
I took Tamoxifen for 5 1/2 years. I am one of the rare ones with the side effect of Chemo-brain; Chemo fog. This is where the medication of the tamoxifen pentrates the brain membrain of the brain and causes prement damage. I have conative brain damage which affects the short term memory and how the brain processes infomation. When I started on Tamoxifen this information was not listed as one[Show More]I took Tamoxifen for 5 1/2 years. I am one of the rare ones with the side effect of Chemo-brain; Chemo fog. This is where the medication of the tamoxifen pentrates the brain membrain of the brain and causes prement damage. I have conative brain damage which affects the short term memory and how the brain processes infomation. When I started on Tamoxifen this information was not listed as one of the side effects. Now I am 100% disabled with a trustee appointed by Social Security for the brain damage caused by the drug called \\\"TAMOXIFEN\\\" Just be ware of this life changing effect!
marlisOctober 4, 2009 at 4:12 am
I recently had a blood clot in my left knee that went to both my lungs and caused a double pulmonary embolism after being on tamoxifen for 6 months. I previously had a total hysterectomy caused by taking tamoxifen for 6 months. my nurse stated that there are many,many people on coumadin because of blood clots caused by tamoxifen
MelissaSeptember 27, 2009 at 3:47 am
my mom died in 2002... she was on tamoxifen for 5 years and discovered she had cancer in her liver and lungs.. she was stage 1 breast cancer before she went on tamoxifen... she wass 55 and extremely healthy with every single lymph node clear... there is no doubt the tamoxifen killed her...
SharonAugust 27, 2009 at 11:02 pm
Gosh this is scarey news. I am a breast cancer survivor. I have been on tamoxifen going on 4 years now. Breast cancer runs in my family. My mother God rest her soul died from it. I had a double masectomy and chemo treatments and currently on tamoxifen. I have a appt. with my oncologist on Sept 1st I will definetally talk to her about what I read. I havent been feeling real good lately and actually[Show More]Gosh this is scarey news. I am a breast cancer survivor. I have been on tamoxifen going on 4 years now. Breast cancer runs in my family. My mother God rest her soul died from it. I had a double masectomy and chemo treatments and currently on tamoxifen. I have a appt. with my oncologist on Sept 1st I will definetally talk to her about what I read. I havent been feeling real good lately and actually got on the computer to do research on tamoxifen. I have had numbness in my fingers and wanted to see if that was one of the side effects. I was also going to talk to her about the hot flashes. I currently am not taking anything for them but they are getting unbearable. So, after reading this I'm not going to let you perscribe me a antidepressant.