By Rebecca Bowers

EXECUTIVE SUMMARY

Results of a large-scale study indicated that 70% of women with a common type of breast cancer do not experience a benefit from chemotherapy. Data suggest that for women with hormone receptor-positive, human epidermal growth factor receptor 2-negative, axillary lymph node-negative breast cancer, post-surgery combination chemotherapy and hormone therapy treatment provides no additional benefit over hormone therapy on its own.

  • Results from the Trial Assigning Individualized Options for Treatment trial offer clinicians data that can lead to treatments that are individualized, researchers say.
  • Until now, clinicians could recommend treatment for women who had cancers with high and low recurrence risk, but the right strategy for patients at intermediate risk has been unclear.

Time to update your practice: Results of a large-scale study indicate that chemotherapy does not benefit 70% of women who have a common type of breast cancer.1 Data suggest that for women with hormone receptor-positive (HR-positive), human epidermal growth factor receptor 2-negative (HER2-negative), axillary lymph node-negative breast cancer, post-surgery treatment with chemotherapy and hormone therapy is no more helpful than hormone therapy treatment on its own.

The Phase 3 clinical trial, known as TAILORx, began in 2006. Researchers used a molecular test, Oncotype DX Breast Recurrence Score, which checks the expression of 21 genes associated with breast cancer recurrence. Results of the test were used to assign more than 10,000 women with early-stage, HR-positive, HER2-negative, axillary lymph node-negative breast cancer to different post-operative treatments. The research sites were in the United States, Australia, Canada, Ireland, New Zealand, and Peru.

Scientists analyzed and assigned each tumor a number on a 0-100 scale risk score for cancer recurrence. By looking at results from previous trials, researchers were able to assign women with a low-risk score to the hormone therapy-only group, while women with high risk were assigned to a group that received hormone therapy and chemotherapy. Researchers randomly assigned those with intermediate-range scores to receive either only hormone therapy or hormone therapy along with chemotherapy.

What Were the Results?

The researchers found that both treatment groups were similar in terms of the proportion of women who survived and who did not have a cancer recurrence or development of a second primary cancer. Findings suggest that the invasive disease-free survival rate was 92.8% for the women who received hormone therapy alone, compared to 93.1% for the women with dual treatment (hormone therapy plus chemotherapy). At the nine-year mark, the rate was 83.3% for women who received only hormone therapy compared to 84.3% for the women who received both treatments.1

The groups also had similar overall survival rates, the researchers reported. For the women who received only hormone therapy, the overall survival rate at five years was 98%, compared to 98.1% for the women who had hormone and chemotherapy treatments. At nine years, the overall survival rates were 93.9% and 93.8%, respectively.1

At the nine-year point, women in the low-risk score group who had only hormone therapy exhibited very low recurrence rates, which was similar to findings from earlier studies, researchers reported. Women in the high-risk score group, who had combined therapy, had a recurrence rate of 13%. Women in this risk group may need more effective therapies, researchers noted.1

Offer Personalized Therapy

These results offer clinicians data that can lead to treatment recommendations that are more individualized, says Joseph Sparano, MD, associate director for clinical research at the Albert Einstein Cancer Center and Montefiore Health System in New York City and vice chair of the ECOG-ACRIN Cancer Research Group, which designed the trial.

“These data confirm that using a 21-gene expression test to assess the risk of cancer recurrence can spare women unnecessary treatment if the test indicates that chemotherapy is not likely to provide benefit,” said Sparano in a press statement. Sparano and colleagues presented the results at the recent American Society of Clinical Oncology annual meeting in Chicago.

What Is Best Treatment Approach?

How might the study’s findings be applied in practice? Based on the trial’s results, approximately 70% of women with HR-positive, HER2-negative, node-negative breast cancer may be able to avoid chemotherapy. This includes:

  • women older than age 50 and who have a recurrence score in the 11-25 range;
  • any age women who have a recurrence score in the 0-10 range; or
  • women age 50 or younger and a recurrence score in the 11-15 range.

For the other 30% of women of any age with HR-positive, HER2-negative, node-negative breast cancer and a recurrence score in the range of 26-100, chemotherapy may be helpful. Women who are age 50 or younger and have a recurrence score of 16-25 also may benefit.

For most women in the group with intermediate risk, the scientists concluded that chemotherapy is not indicated. The current findings are in line with a 2015 TAILORx analysis that indicated prospectively that women who had a low risk of recurrence and could avoid chemotherapy could be determined by the gene expression test.2

When researchers separately analyzed women in the higher intermediate-risk range who were premenopausal and those younger than age 50, the results indicated a small benefit from chemotherapy.1 Such women may consider chemotherapy with their clinician, they state.

Until now, clinicians could recommend treatment for women who had cancers with high and low recurrence risk, but the right strategy for patients at intermediate risk has been unclear, notes Jeffrey Abrams, MD, associate director of the National Cancer Institute’s Cancer Therapy Evaluation Program.

“These findings, showing no benefit from receiving chemotherapy plus hormone therapy for most patients in this intermediate-risk group, will go a long way to support oncologists and patients in decisions about the best course of treatment,” said Abrams in a press statement.

REFERENCES

  1. Sparano JA, Gray RJ, Makower DF, et al. Adjuvant chemotherapy guided by a 21-gene expression assay in breast cancer. N Engl J Med 2018; doi: 10.1056/NEJMoa1804710.
  2. Sparano JA, Gray RJ, Makower DF, et al. Prospective validation of a 21-gene expression assay in breast cancer.
    N Engl J Med 2015;373:2005-2014.