Controversy over the established optimal treatment strategy for women with node-negative breast cancer (cancer has not spread to any lymph nodes) whose cancer is 1cm or smaller, has existed since the 1960’s. 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 (treatment following initial therapy). Results from the following clinical trials help to define optimal treatment options for patients with early-stage, node-negative breast cancer.
Adjuvant Chemotherapy and/or Tamoxifen Reduces Local Recurrences
Recently, researchers affiliated with the National Surgical Adjuvant Breast and Bowel Project (NSABP) have reported statistical data from several clinical trials indicating that women with node-negative breast cancer whose cancer is 1cm or smaller appear to derive significant 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.
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. 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. Optimal adjuvant regimens for ER-positive patients included tamoxifen plus chemotherapy. 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)
Tamoxifen of No Benefit for Estrogen-Negative Breast Cancer
Researchers from the NSABP also evaluated outcomes from a large clinical trial involving women with early-stage breast cancer who received adjuvant doxorubicin/cyclophosphamide (AC) or cyclophosphamide/methotrexate/fluorouracil (CMF) with or without tamoxifen. In this study 2,008 women with node-negative, ER-negative breast cancer were randomly assigned to receive CMF plus placebo (inactive substitute), CMF plus tamoxifen, AC plus placebo, or AC plus tamoxifen. Patients who received AC had the same outcome as patients who received CMF. In addition, patients who received either tamoxifen or placebo with either chemotherapy regimen had the same outcome. These results are important as they clearly indicate that patients with ER-negative breast cancer do not benefit from tamoxifen, and this drug may be omitted from the adjuvant regimen of such patients. (Journal of Clinical Oncology, Vol 19, Issue 4, pp. 931-942, 2001)
No Benefit From More Than 5 Years of Tamoxifen
Researchers from the NSABP have previously determined that women with ER-positive, node-negative breast cancer benefit from 5 years of tamoxifen compared to less than 5 years of tamoxifen. Recent results, however, indicate that treatment with tamoxifen beyond 5 years is not of further benefit.
This conclusion is based on a study involving ER-positive, node-negative breast cancer patients who had completed 5 years of successful therapy with tamoxifen. After the initial 5 years of treatment, patients received either 2 more years of tamoxifen or placebo. Survival was 94% for patients who discontinued tamoxifen after 5 years and 92% for patients who continued receiving tamoxifen for a total of 7 years. There were no differences in the development of cancer recurrences between the two groups of patients. Results from this clinical trail indicate that treatment involving tamoxifen appears to have no added benefit after 5 years in women with ER-positive, node-negative breast cancer. (Journal of the National Cancer Institute, Vol 93, No. 9, pp. 662-664, 684-690, 2001)
Women with early stage, node-negative breast cancer may wish to speak with their physician about the risks and benefits of receiving adjuvant chemotherapy and/or hormonal therapy or participating in a clinical trial further evaluating adjuvant therapies. Two sources of information regarding ongoing clinical trials include comprehensive, easy-to-use listing services provided by the National Cancer Institute (cancer.gov) and eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients.