Adjuvant Chemotherapy has Improved Survival of Women with Primary Breast Cancer

Adjuvant Chemotherapy has Improved Survival of Women with Primary Breast Cancer

A recent article in the journal Cancer reports that the current strategy of treating breast cancer with chemotherapy and hormonal therapy has altered the natural history of this group of high-risk patients.[1]

Breast cancer is a malignancy associated with the tissues of the breast. When a diagnosis of breast cancer is made, various tests are performed to further describe the features of the cancer. One test determines whether the cancer was supported by the hormones estrogen and progesterone. If the cancer is found to be estrogen or progesterone positive, then treatment may consist of drugs, such as tamoxifen (Nolvodex®), which prevent the hormones from reaching the breast cancer cells. Other testing and biopsies will also be performed to determine if the cancer has spread to the surrounding lymph nodes. Patients with breast cancer who have more than 10 lymph nodes involved with their disease have a significant chance that their cancer will recur within five years of diagnosis. In this recent study, researchers sought to describe the natural history of this disease both before and after chemotherapy and hormonal therapies became the mainstay of treatment.

Researchers evaluated the charts and history of 882 patients with more than 10 positive lymph nodes who were treated between 1954 and 1998. The patient data was gathered from three different institutions: The University of Texas M.D. Anderson Cancer Center (Houston, Texas); the Institut Gustave Roussy (Villejuif, France); and Hospital Clinico Universitario (Valencia, Spain). The patient data was separated into two groups. One group consisted of 314 patients treated with local therapy (surgery or radiation) only (no chemotherapy) between the years of 1954 and 1983. The second group consisted of 568 patients who received chemotherapy with anthracycline-based chemotherapy between the years of 1974 and 1998, with or without tamoxifen.

Observations were made at an average follow-up of 140 months. At 15 and 20 years, the disease-free survival rate among the group who had received only local therapy was 17% and 16%. Patients who had received chemotherapy with or without hormonal therapy showed more positive results: disease-free survival rates at 15 and 20 years were 26% and 24%. The overall survival rate for the patients who received local therapy alone was 9%, while the rate for those who received chemotherapy with or without tamoxifen more than doubled that number at 21%. Further analysis revealed that other factors that impact survival rates included the tumor size and the number of lymph nodes involved.

Researchers concluded that the review of these cases of breast cancer indicates that chemotherapy and hormonal therapy have altered the natural course of history for this high-risk group of patients. However, despite these advances, survival rates remain low among breast cancer patients with disease that has spread extensively through the lymph nodes. A recent randomized trial evaluated high-dose chemotherapy versus intensive adjuvant therapy for treatment of 785 women with stage II-III breast cancer with 10 or more positive lymph nodes. The probability of being alive and disease-free after 5 years was 61% for the high-dose arm and only slightly lower at 58% for the intensive adjuvant arm.[2] Overall survival at 5 years was 71%. These data suggest that there has been even further improvement in the adjuvant chemotherapy treatment of patients with localized breast cancer with 10 or more positive lymph nodes. These results also suggest that women may have improved survival by participating in clinical trials. Researchers are hopeful that continued research to develop new therapeutic approaches will continue to improve clinical outcomes.

References:

[1] Montero A, Rouzier R, Lluch A, et al. The Natural History of Breast Carcinoma in Patients with >10 Metastatic Lymph Nodes Before and After the Advent of Adjuvant Therapy. Cancer. 104: 229-235.

[2] Peters WP, Rosner GL, Vredenburgh JJ, et al. Prospective, randomized comparison of high-dose chemotherapy with stem-cell support versus intermediate-dose chemotherapy after surgery and adjuvant chemotherapy in women with high-risk primary breast cancer: a report of CALGB 9082, SWOG 9114, and NCIC MA-13.

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