image of woman after chemotherapy
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This article waslast modified on July 27, 2018.

More women with certain early breast cancers (stage IA, hormone-receptor positive, HER2 negative, node-negative) can avoid chemotherapy using Oncotype DX Breast, a genetic tumor test that quantifies the risk of recurrence. New results from an ongoing clinical trial reported in the New England Journal of Medicine show that about 70% of women with mid-range recurrence scores on the test can omit chemotherapy from their treatment plan without risking their chance of beating the disease.

Breast cancer typically is treated with some combination of surgery, radiation, chemotherapy, and/or other drug therapies based on several factors, such as tumor size, stage and presence of genetic mutations. These mutations and the change to the expression of those genes control how rapidly the tumor grows, its likelihood of spreading (metastasizing), whether the tumor’s growth is promoted by the hormones estrogen or progesterone, whether it over-expresses certain proteins such as HER2, and how responsive the tumor will be to specific treatments.

Participants in the ongoing Trial Assigning IndividuaLized Options for Treatment (Rx) (TAILORx) include women ages 18 to 75 who have or had hormone-receptor positive, HER-2 negative breast cancer that has not spread to the lymph nodes (node-negative). These breast cancers account for about half of all cases in the United States.

All participants had their tumors tested using Oncotype DX Breast, a gene expression test that quantifies the risk of a tumor returning after successful treatment (recurrence) by measuring the activity of 21 genes in a breast tumor sample that are associated with cell growth and treatment response. The gene activity profile is assigned a recurrence score from 0 to 100, with a higher score translating to a greater chance the cancer will recur in the next 10 years.

Previous reports from TAILORx showed that women with low recurrence scores (10 or lower) did not benefit from chemotherapy and women with high scores (over 25) should be advised by their healthcare practitioners to have chemotherapy. The new TAILORx report focused specifically on the 6,711 women who had mid-range recurrence scores of 11 to 25—the largest group of women enrolled in the study (69%).

All of the women enrolled in TAILORx with mid-range recurrence scores had surgery and estrogen-blocking hormone therapy, while only half received chemotherapy. After nine years, the percentage of women still alive in each group was roughly the same (94%) and both groups had about the same rate of women with no recurrence of cancer (84% in the chemotherapy group versus 83% in the group without chemotherapy). Therefore, the TAILORx administrators concluded that adding chemotherapy to this mid-range group's treatment made no difference in their outcomes. However, for women ages 50 and under with recurrence scores on the higher end of the mid-range scale (16 to 25), treatment outcomes were better if they received chemotherapy.

Based on these results, the TAILORx study authors recommend that the following women with hormone-receptor positive, HER2-negative, lymph node-negative breast cancer forgo chemotherapy:

  • Women over the age of 50 with an Oncotype DX recurrence score of 0 to 25 (about 85% of women in this age group)
  • Women ages 50 and under with an Oncotype DX recurrence score of 0 to 15 (about 40% of women in this age group)

"With results of this groundbreaking study, we now can safely avoid chemotherapy in about 70 percent of patients who are diagnosed with the most common form of breast cancer," said the study's senior author, Kathy S. Albain, M.D., Professor of Medicine at the Loyola University School of Medicine. This translates to about 70,000 patients per year in the United States who don't have to face the financial stress or side effects of chemotherapy drugs.

Safely forgoing chemotherapy with guidance from the Oncotype DX Breast test can mean avoiding possible short- and long-term side effects without risking recurrence of breast cancer.

View Sources

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Fisher, A. (June 3, 2018) American Society of Clinical Oncology, Press Release. Most women with early stage breast cancer can forgo chemotherapy when guided by a diagnostic test. Available online at www.asco.org/about-asco/press-center/news-releases/most-women-early-stage-breast-cancer-can-forgo-chemotherapy. Accessed on June 26, 2018.

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Ashford, M. (June 3, 2018) GenomeWeb. Fewer breast cancer patients benefit from chemo, TAILORx study with Oncotype DX finds. Available online at www.genomeweb.com/molecular-diagnostics/fewer-breast-cancer-patients-benefit-chemo-tailorx-study-oncotype-dx-finds#.WzItOy2B3BJ. Accessed on June 26, 2018.

(February 14, 2017) Breastcancer.org. Managing chemotherapy side effects. Available online at www.breastcancer.org/treatment/chemotherapy/side_effects. Accessed on June 26, 2018.

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