Chemotherapy Improves Survival for Early Hormone-negative Breast Cancer

Posted on January 4th, 2008 by

Chemotherapy Improves Survival for Early Hormone-negative Breast Cancer

According to results recently published in the Lancet, findings from a large analysis of several clinical trials indicate that adjuvant chemotherapy improves outcomes, including survival, among women with early estrogen receptor-negative breast cancer.

Early breast cancer refers to cancer that has not spread from the breast to distant sites in the body. The majority of breast cancers are estrogen-receptor (ER)-positive, or hormone-positive. These cancers are stimulated to grow from exposure to the circulating female hormones estrogen and/or progesterone. Patients with ER-positive breast cancers are treated with hormone therapy, which blocks estrogen's ability to stimulate cellular growth or replication of cancer cells, or with hormone therapy plus chemotherapy. However, because patients with ER-negative breast cancer do not benefit from hormone therapy, they are most often treated with adjuvant chemotherapy alone.

More-recent results have demonstrated that many patients with early ER-positive breast cancer may not benefit from the addition of chemotherapy to hormone therapy. Because chemotherapy is associated with significant side effects, researchers continue to evaluate its potential risks and benefits, particularly among women with early breast cancer.

Researchers associated with the Early Breast Cancer Trialists' Collaborative Group recently conducted an analysis of data from approximately 20,000 women with ER-negative breast cancer who had participated in several different clinical trials. The analysis included approximately 6,000 women who had participated in 46 clinical trials; these trials evaluated chemotherapy regimens that did not contain taxanes (class of chemotherapy agents including Taxol® [paclitaxel] and Taxotere® [docetaxel]). Also included in the analysis were approximately 14,000 women who had participated in 50 clinical trials; these trials compared treatment with tamoxifen (Novaldex®), a hormone agent, and/or chemotherapy, or no therapy following the surgical removal of their cancer.

At 10 years follow-up, these results were reported for patients 50 years of age or younger:

  • Recurrences of cancer were significantly reduced (from 44% to 33%) among patients younger than 50 years of age who were treated with combination chemotherapy.
  • Mortality from breast cancer was also reduced by 8% among patients younger than 50 years of age who were treated with combination chemotherapy.
  • Death from any cause was also significantly reduced among patients who were treated with combination chemotherapy.

At 10 years of follow-up, these results were reported for patients 50 years of age or older:

  • Cancer recurrences were reduced by 10% among patients who were treated with combination chemotherapy.
  • Mortality from breast cancer was 36% among patients treated with combination chemotherapy compared with 42% for those not treated with combination chemotherapy.
  • Death from any cause was also significantly reduced among patients who were treated with combination chemotherapy.

Overall, tamoxifen did not affect treatment outcomes and did not affect outcomes when used with chemotherapy.

The researchers concluded that combination chemotherapy significantly improves survival among women with early ER-negative breast cancer. Research efforts are now focused on identifying the optimal chemotherapy regimens for these patients.

Reference: Early Breast Cancer Trialists' Collaborative Group. Adjuvant chemotherapy in estrogen-receptor-poor breast cancer: patient-level meta-analysis of randomized trials. Lancet 2008; 371: 29-40.

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