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After 2-3 Years of Tamoxifen, 5 Years of Femara Offers More Benefits Than 2-3 Years

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After taking the hormonal therapy medicine tamoxifen for 2 to 3 years following surgery, postmenopausal women diagnosed with early-stage hormone-receptor-positive breast cancer had a better survival rate from taking 5 years of Femara (chemical name: letrozole) rather than 2 to 3 years of Femara, according to an Italian study.

The research was presented on Sept. 17, 2021, at the European Society for Medical Oncology (ESMO) Congress 2021 and published at the same time in The Lancet Oncology:

Doctors call treatments given after surgery adjuvant treatments.

About hormonal therapy
About the study
What this means for you

About hormonal therapy

After surgery, people diagnosed with early-stage hormone-receptor-positive breast cancer usually take hormonal therapy medicine to reduce the risk of the cancer coming back (recurrence).

Hormonal therapy medicines work in two ways:

  • by lowering the amount of estrogen in the body
  • by blocking the action of estrogen on breast cancer cells

There are several types of hormonal therapy medicines. Tamoxifen — a selective estrogen receptor modulator (SERM) — is one of the most well-known. Both premenopausal and postmenopausal women can take tamoxifen. In the early 2000s, the following aromatase inhibitors proved to be more effective at reducing recurrence risk in postmenopausal women:

  • Arimidex (chemical name: anastrozole)
  • Aromasin (chemical name: exemestane)
  • Femara

Doctors now prescribe these three aromatase inhibitors more often than they prescribe tamoxifen for women who’ve gone through menopause. Aromatase inhibitors aren’t commonly used to reduce recurrence risk in premenopausal women.

For many years, women took hormonal therapy for 5 years after breast cancer surgery. In most cases, the standard of care was 5 years of tamoxifen, or 2 to 3 years of tamoxifen followed by 2 to 3 years of an aromatase inhibitor, depending on menopausal status.

Then research found that taking tamoxifen for 10 years instead of 5 years after surgery lowered a woman’s risk of recurrence and improved survival. Taking tamoxifen for 10 years after surgery became the standard of care in 2014.

In 2018, the American Society of Clinical Oncology (ASCO) updated its guidelines on adjuvant hormonal therapy, recommending postmenopausal women diagnosed with early-stage hormone-receptor-positive breast cancer that has spread to the lymph nodes (node-positive disease) receive hormonal therapy treatment, including an aromatase inhibitor, for 10 years after surgery. Doctors call taking hormonal therapy for 10 years after surgery extended adjuvant hormonal therapy.

Still, aromatase inhibitors can cause a number of troubling side effects, including hot flashes, joint pain, and bone pain. In some cases, the side effects are so bothersome that women stop taking the medicine early. Aromatase inhibitors also can cause osteoporosis, which increases the risk of breaking a bone.

The researchers who did this study wanted to see if taking 5 years of Femara offered more benefits than 2 to 3 years of Femara following 2 to 3 years of tamoxifen for postmenopausal women diagnosed with early-stage hormone-receptor-positive breast cancer.

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About the study

Conducted at 69 hospitals in Italy, the study included 2,056 postmenopausal women diagnosed with stage I to stage III hormone-receptor-positive breast cancer. All the women had surgery to remove the breast cancer and then took tamoxifen for 2 to 3 years.

After the women completed 2 to 3 years of tamoxifen, the researchers randomly assigned them to one of two treatment groups:

  • 1,030 women took Femara for 2 to 3 years
  • 1,026 women took Femara for 5 years

About 40% of the women in each treatment group had node-positive breast cancer, and about 55% of the women in each treatment group had received chemotherapy before surgery.

Half the women were followed for more than 11.7 years, and half were followed for shorter periods of time.

Overall, 80% of the women taking Femara for 2 to 3 years completed the full course of treatment, and 63% of the women taking Femara for 5 years completed the full course of treatment. In both groups, side effects were the main reason the women stopped treatment early.

Twelve-year disease-free survival rates were:

  • 67% for women who took 5 years of Femara
  • 62% for women who took 2 to 3 years of Femara

The 12-year disease-free rate is the percentage of women who were alive with no cancer recurrence after 12 years.

This difference in disease-free survival rates was statistically significant, which means that it was likely because of the difference in treatment and not due to chance.

Twelve-year overall survival rates were:

  • 88% for women who took 5 years of Femara
  • 84% for women who took 2 to 3 years of Femara

The 12-year overall survival rate is the percentage of women who were alive, whether or not the cancer came back, after 12 years.

This difference also was statistically significant.

The most common grade 3 or 4 side effects in both treatment groups were:

  • joint pain: 2% in the 2-to-3-year group vs. 3% in the 5-year group
  • muscle pain: 1% in both groups

Other common side effects were:

  • hot flashes: 12%-13% in both groups
  • hair loss: 3%-4% in both groups
  • osteoporosis: 5%-8% in both groups
  • high blood pressure: 1%-2% in both groups

“Sequential endocrine therapy with tamoxifen for 2 to 3 years followed by letrozole for 5 years should be considered as one of the optimal standard endocrine treatments for postmenopausal patients with hormone-receptor-positive breast cancer,” said Lucia Del Mastro, M.D., professor of oncology at the University of Genoa, who presented the research.

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What this means for you

If you’re a postmenopausal woman who’s been diagnosed with early-stage hormone-receptor-positive breast cancer, you will likely take some type of hormonal therapy medicine after surgery.

If your doctor recommends Femara for 2 to 3 years after 2 to 3 years of tamoxifen, it’s a good idea to bring up this study and ask whether it may be possible to take Femara for 5 years instead of 2 to 3 years. Together, you can decide on the best hormonal therapy treatment plan for your unique situation.

It’s also very important to talk to your doctor if you’re having troublesome side effects from the hormonal therapy medicine. There are ways to manage these side effects, including acupuncture, exercise, and medicine. You also may be able to switch to a different hormonal therapy.

Learn more about Hormonal Therapy.

To talk with others about your hormonal therapy experiences, join the Hormonal Therapy - Before, During, and After Discussion Board forum.

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Written by: Jamie DePolo, senior editor


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