Recent findings from the Trial Assigning Individualized Options for Treatment (Rx), also known as the TAILORx trial, show that chemotherapy is not beneficial to the most commonly found form of breast cancer. Sponsored by the National Cancer Institute (NCI), researchers found that chemotherapy does not benefit 70 percent of women with estrogen receptor-positive, HER2-negative, axillary lymph node-negative breast cancer. Hormone therapy combined with chemotherapy is not more beneficial than treating breast cancer with hormone therapy alone. Researchers released this data at the American Society of Clinical Oncology’s annual meeting this year in Chicago.
Details of the study
Beginning in 2006, researchers conducted this study to examine the effectiveness of hormone therapy alone compared to using both hormone therapy and chemotherapy in treating breast cancer. The study divided women into two groups. The groups were based on the individual woman’s genes that determine their risk of cancer recurrence. This would be determined by a molecular test that examines their tumors. It is known as the Oncotype DX Breast Recurrence Score. The test examines 21 genes associated with breast cancer recurrence. Each participant’s tumors were analyzed using this test. They were each assigned a risk score that was on a scale from 0-100. The higher the score, the higher the recurrence risk. Women who had a score of 0-10 received hormone therapy only. Women who had a score of 26 and above were considered high-risk and given chemotherapy. Women who had a score of 11-25 were randomly assigned to receive just hormone therapy or hormone therapy and chemotherapy.
Researchers found similar results between the group who underwent hormone therapy and the group who underwent both hormone therapy and chemotherapy. They found that the proportion of women who survived or not developed a recurring or another cancer was very similar for both groups. After five years of treatment, the rate for women who received only hormone therapy was 92.8 percent, while the rate for women who received both hormone therapy and chemotherapy was 93.1 percent. After nine years, the rate was 83.3 for women who received only hormone therapy, while the rate of women who received both therapies was 84.3 percent.
The survival rates were also similar for both groups. After five years, it was 98 percent for women who received only hormone therapy, while it was 98.1 for women who received both. At nine years, the rates were 93.9 for women who received only hormone therapy and 93.8 for women who received both.
Regarding women who had a score of 0-10, the recurrence rate was three percent after nine years. They also found that a woman with a score of 26 or above also had a recurrence rate of 13 percent, even though they took both hormone therapy and chemotherapy.
These results show that about 70 percent of women with estrogen receptor-positive, HER2-negative, axillary lymph node-negative breast cancer can avoid chemotherapy altogether. This group includes women over 50 with a score of 11-25, women of any age with a score of 0-10, and women 50 and under with a score of 11-15. The remaining 30 percent comprises women of all ages with a score of 26-100 and women over 50 with a score of 16-25. This indicates that a gene expression test can help determine the risk of cancer recurrence. It can help determine whether or not one needs to undergo chemotherapy treatment.
However, researchers found that some women under 50 could benefit from chemotherapy. This consists of premenopausal women and women under 50 who received a score of 16-25. Researchers suggest that these women should ask their doctor about undergoing chemotherapy. Despite this, researchers are unsure if this is because chemotherapy is beneficial or chemotherapy-induced menopause causes endocrine suppression.
Why is this study significant?
This study is significant because it suggests that many cancer patients do not need to undergo chemotherapy. The problem, of course, is that we do not know who it works with and how it does not. Some cancer patients might not need to endure chemotherapy’s debilitating side effects that negatively impact a patient’s well-being. These side effects include a low white blood cell count, hair loss, nausea, vomiting, and lymphedema.
Having a low white blood cell count can increase the risk of getting an infection, which could create further complications. By only taking hormone therapy, cancer patients do not have to experience chronic nausea and vomiting resulting from undergoing chemotherapy. Lymphedema can increase swelling, which can be physically debilitating. They also do not have to take extra medications that alleviate chemotherapy’s side effects.