Data analyzed from 5 large clinical trials conducted by the National Surgical Adjuvant Breast and Bowel Project (NSABP) indicate that the use of adjuvant chemotherapy (treatment following primary treatment) improves disease-free survival in women with node negative breast cancer. These results, recently published in the
Journal of the National Cancer Institute, have been compiled from trials involving nearly 12,000 women whose cancer was 1cm or smaller, with a follow-up of 8 to 14 years to determine long-term effects of treatment.
Controversy over the established optimal treatment strategy for women with node negative (cancer has not spread to any lymph nodes) breast cancer whose cancer is 1cm or smaller, has existed since the 1960s. Since women with this stage of cancer have a good prognosis following treatment with mastectomy or lumpectomy and radiation, patients often are not offered adjuvant chemotherapy.
Recently, the NSABP has reported statistical data indicating that women with node negative breast cancer whose cancer is 1cm or smaller may derive long-term survival benefit from adjuvant chemotherapy. Women enrolled in these clinical trials were divided into two groups: those with estrogen receptor (ER) negative breast cancer, meaning their cancer is not stimulated to grow by the female hormone estrogen, and those with ER positive breast cancer, meaning their cancer is stimulated to grow by estrogen. Patients from each group received local treatment with either surgery alone (mastectomy or lumpectomy and radiation) or surgery plus adjuvant chemotherapy consisting of methotrexate and 5-fluorouracil with or without cyclophosphamide. Tamoxifen, a compound which blocks the growth effects of estrogen on cancer cells, was also administered to women with ER positive breast cancer.
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The extensive data revealed that women with ER negative breast cancer had a disease-free survival rate of 81% when treated with surgery alone compared to 90% when treated with surgery plus adjuvant chemotherapy. Overall survival was comparable between the two treatment groups. For women with ER positive breast cancer, disease-free survival was improved by approximately 10% when they were treated with adjuvant chemotherapy and tamoxifen (95%) compared with surgery alone (86%). Moreover, overall survival for patients with ER positive breast cancer was 90% with surgery alone compared with 97% when adjuvant chemotherapy and tamoxifen were used. ER positive patients achieved a much higher survival when chemotherapy was combined with tamoxifen versus tamoxifen alone.
These results clearly indicate an improved disease-free and overall survival for patients with node-negative, small breast cancers when adjuvant chemotherapy was added to their treatment regimen. With the expanding use of screening methods that are becoming more sensitive, more women will be diagnosed earlier for breast cancer. Therefore, it is important that these patients at least be offered the choice of receiving adjuvant treatment in the form of chemotherapy, as large-scale results appear to indicate that long-term benefit is derived through this treatment option. (Journal of the National Cancer Institute, Vol 93, No 2, pp 112-120, 2001)
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