Two Years of Hormonal Therapy Offers 20 Years of Benefits

Two Years of Hormonal Therapy Offers 20 Years of Benefits

Two years of hormonal therapy after surgery to remove estrogen receptor-positive breast cancer in pre-menopausal women helped reduce the risk of metastatic recurrence for 20 years.
Sep 8, 2022.
 

Two years of hormonal therapy after surgery to remove early-stage, estrogen receptor-positive breast cancer in pre-menopausal women helped reduce the risk of metastatic recurrence for 20 years, according to a Swedish study.

The research was published online on July 21, 2022, by the Journal of Clinical Oncology. Read the abstract of “Twenty-Year Benefit From Adjuvant Goserelin and Tamoxifen in Premenopausal Patients With Breast Cancer in a Controlled Randomized Clinical Trial.”

Metastatic recurrence is when breast cancer comes back in a part of the body away from the breast, such as the bones, liver, or lungs.

Doctors call treatments after surgery adjuvant treatments.

 

About hormonal therapy

Hormonal therapy, also called anti-estrogen therapy, endocrine therapy, or hormone therapy, is used to treat all stages of hormone receptor-positive breast cancer.

The are several hormonal therapy medicines, including tamoxifen and Zoladex (chemical name: goserelin).

Tamoxifen blocks the effects of estrogen on hormone receptor-positive breast cancer cells by sitting in the estrogen receptors on the cells. If tamoxifen is in the receptor, estrogen can’t attach itself to the cancer cell, and the cell doesn’t receive estrogen’s signals to grow and multiply. Tamoxifen is used to treat early-stage, hormone receptor-positive disease in women who are pre- and post-menopausal and in men. People typically take five to 10 years of tamoxifen after surgery.

In pre-menopausal women, the ovaries make most of the estrogen in the body. Zoladex is used to temporarily stop the ovaries from functioning, called ovarian suppression or ovarian shutdown. This dramatically lowers the amount of estrogen in the body.

Zoladex is given as an injection once a month or every few months.

Doctors often recommend ovarian suppression along with tamoxifen after surgery for pre-menopausal women diagnosed with early-stage breast cancer with a high risk of recurrence based on the characteristics of the cancer, including positive lymph nodes and a high cancer grade.

 

About the study

We know that early-stage, hormone receptor-positive breast cancer can have metastatic recurrence more than 10 years after the initial diagnosis. Many studies have shown that taking five to 10 years of hormonal therapy after surgery reduces the risk of recurrence, as does ovarian suppression. Still, few studies have followed people for more than 10 years.

Called the Stockholm trial, this study looked at the benefits of tamoxifen and Zoladex after surgery for pre-menopausal women diagnosed with early-stage, estrogen receptor-positive breast cancer. These latest results include 20 years of follow-up.

The analysis included 584 pre-menopausal women diagnosed with estrogen receptor-positive breast cancer. All the women had surgery to remove the cancer. Half the women were younger than 47 and half were older.

After surgery, the researchers randomly assigned the women to one of four hormonal therapy treatment groups:

  • 135 women took tamoxifen once a day for two years

  • 155 women received Zoladex once every 28 days for two years

  • 149 women took tamoxifen and received Zoladex

  • 145 women received no hormonal therapy after surgery

Women who had positive lymph nodes also received chemotherapy after surgery. Women who had four or more positive lymph nodes also received radiation therapy.

The researchers also did MammaPrint genomic testing on breast cancer. The MammaPrint test analyzes a sample of a cancer tumor to see the activity levels of 70 genes so it can calculate whether recurrence is low risk or high risk.

Of the 463 estrogen receptor-positive breast cancers the researchers tested with MammaPrint:

  • 158 were high risk

  • 305 were low risk

After a minimum of 20 years of follow-up, women who received any type of hormonal therapy after surgery had a lower risk of metastatic recurrence than women who received no hormonal therapy. Versus women who received no hormonal therapy:

  • women who took tamoxifen had a 43% lower risk of metastatic recurrence

  • women who received Zoladex had a 51% lower risk of metastatic recurrence

  • women who took tamoxifen and received Zoladex had a 37% lower risk of metastatic recurrence

Women diagnosed with cancers classified as low risk by MammaPrint benefited more from tamoxifen, and women diagnosed with cancers classified as high risk by MammaPrint benefited more from Zoladex.

The results showed that tamoxifen offered benefits for low-risk cancers from year four to year 20. Zoladex offered benefits for high-risk cancers from year one to year eight.

“Results from the [Stockholm] trial with a 20-year follow-up suggest a long-term benefit from two years of adjuvant endocrine therapy in [estrogen receptor]-positive premenopausal patients,” the researchers concluded. “For patients unable to endure five years of endocrine therapy, the significant benefit from two years of treatment as seen in this study could be helpful for both patients and clinicians. However, further studies are needed to understand the optimal treatment duration.”

 

What this means for you

If you’ve been diagnosed with early-stage, hormone receptor-positive breast cancer, your doctor is likely to recommend five to 10 years of hormonal therapy after surgery to reduce the risk of recurrence. Doctors usually prescribe tamoxifen for pre-menopausal women.

Still, tamoxifen can cause troubling side effects such as hot flashes and night sweats. Less common but more severe side effects include blood clots and endometrial cancer.

Research has shown that about 25% of women who are prescribed hormonal therapy to reduce the risk of recurrence after surgery either don’t start taking the medicine or stop taking it early, in many cases because of side effects.

So this study offers some good news for women who are unable to take tamoxifen for five years. Taking the medicine for only two years offered benefits for up to 20 years.

But the study doesn’t tell us if women who took tamoxifen for five years got more benefits from the medicine than women who took tamoxifen for two years.

We know that breast cancer — especially hormone receptor-positive breast cancer — can come back 10 to 30 years after the initial diagnosis. It’s very important that you take the medicine your doctor recommends to you at the correct dose and for as long as it’s prescribed.

It’s also very important to talk to your doctor right away before any troubling side effects become intolerable and you have to stop taking the medicine. There are steps you can take to ease these side effects, including switching to a different type of hormonal therapy.

Learn more about Planning Your Breast Cancer Treatment to see why it’s so important to stick to your treatment plan and for ways to manage side effects after radiation, chemotherapy, and hormonal therapy.

To talk with others about staying on track with hormonal therapy treatment, join the conversation on Hormonal Therapy - Before, During, and After in our community.

Written by: Jamie DePolo, senior editor

— Last updated on September 23, 2022, 6:23 PM

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