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Background: Most recurrences in women with breast cancer receiving 5 years of adjuvant tamoxifen occur after 5 years. The MA.17 trial, which was designed to determine whether extended adjuvant therapy with the aromatase inhibitor letrozole after tamoxifen reduces the risk of such late recurrences, was stopped early after an interim analysis showed that letrozole improved disease-free survival. This report presents updated findings from the trial. Methods: Postmenopausal women completing 5 years of tamoxifen treatment were randomly assigned to a planned 5 years of letrozole (n = 2593) or placebo (n = 2594). The primary endpoint was disease-free survival (DFS); secondary endpoints included distant disease-free survival, overall survival, incidence of contralateral tumors, and toxic effects. Survival was examined using Kaplan-Meier analysis and log-rank tests. Planned subgroup analyses included those by axillary lymph node status. All statistical tests were two-sided. Results: After a median follow-up of 30 months (range = 1.5–61.4 months), women in the letrozole arm had statistically significantly better DFS and distant DFS than women in the placebo arm (DFS: hazard ratio [HR] for recurrence or contralateral breast cancer = 0.58, 95% confidence interval [CI] = 0.45 to 0.76; P«.001; distant DFS: HR = 0.60, 95% CI = 0.43 to 0.84; P = .002). Overall survival was the same in both arms (HR for death from any cause = 0.82, 95% CI = 0.57 to 1.19; P = .3). However, among lymph node-positive patients, overall survival was statistically significantly improved with letrozole (HR = 0.61, 95% CI = 0.38 to 0.98; P = .04). The incidence of contralateral breast cancer was lower in women receiving letrozole, but the difference was not statistically significant. Women receiving letrozole experienced more hormonally related side effects than those receiving placebo, but the incidences of bone fractures and cardiovascular events were the same. Conclusion: Letrozole after tamoxifen is well-tolerated and improves both disease-free and distant disease-free survival but not overall survival, except in node-positive patients. [ABSTRACT FROM AUTHOR]

The article discusses the results from an International Breast Cancer Study Group (IBCSG) trial that examines the role of ovarian suppression in the management of localized, newly diagnosed breast cancer in premenopausal women. The IBCSG trial compared, in a group of premenopausal patients, three treatment strategies, the cyclophosphamide, methotrexate, 5-fluorouracil (CMF) chemotherapy, CMF followed by ovarian suppression with goserelin and goserelin alone. In a preplanned subgroup analysis, patients with estrogen receptor negative tumors assigned to receive CMF or CMF followed by goserelin had better outcomes than patients assigned to goserelin.

A response by Paul E. Goss, James N. Ingle and Joseph L. Pater to a letter to the editor about their article "Letrozole in Breast Cancer" in the November 6, 2004 issue is presented.

Background: In hormone-dependent breast cancer, five years of postoperative tamoxifen therapy — but not tamoxifen therapy of longer duration — prolongs disease-free and overall survival. The aromatase inhibitor letrozole, by suppressing estrogen production, might improve the outcome after the discontinuation of tamoxifen therapy. Methods: We conducted a double-blind, placebo-controlled trial to test the effectiveness of five years of letrozole therapy in postmenopausal women with breast cancer who have completed five years of tamoxifen therapy. The primary end point was disease-free survival. Results: A total of 5187 women were enrolled (median follow-up, 2.4 years). At the first interim analysis, there were 207 local or metastatic recurrences of breast cancer or new primary cancers in the contralateral breast — 75 in the letrozole group and 132 in the placebo group — with estimated four-year disease-free survival rates of 93 percent and 87 percent, respectively, in the two groups (P≤0.001 for the comparison of disease-free survival). A total of 42 women in the placebo group and 31 women in the letrozole group died (P=0.25 for the comparison of overall survival). Low-grade hot flashes, arthritis, arthralgia, and myalgia were more frequent in the letrozole group, but vaginal bleeding was less frequent. There were new diagnoses of osteoporosis in 5.8 percent of the women in the letrozole group and 4.5 percent of the women in the placebo group (P=0.07); the rates of fracture were similar. After the first interim analysis, the independent data and safety monitoring committee recommended termination of the trial and prompt communication of the results to the participants. Conclusions: As compared with placebo, letrozole therapy after the completion of standard tamoxifen treatment significantly improves disease-free survival. N Engl J Med 2003;349:1793-802. [ABSTRACT FROM AUTHOR]

Background: Although ondansetron was found to be effective as an antiemetic in numerous clinical trials of highly emetogenic combination-chemotherapy regimens that included cisplatin, its role in milder emetogenic regimens has not been fully defined. To address its use with a widely used but less emetogenic regimen, we performed a double-blind, randomized clinical trial comparing ondansetron with dexamethasone and metoclopramide in patients with breast cancer receiving chemotherapy with cyclophosphamide, methotrexate, and fluorouracil. Methods: A total of 165 women with breast cancer from 14 Canadian centers who were about to receive this chemotherapy for the first time were randomly assigned to receive either ondansetron (n = 85) or dexamethasone plus metoclopramide (n = 80), a widely used, standard antiemetic regimen. The patients recorded the incidence of nausea, emesis, and other side effects in diaries, and these data were compared in the two groups. Results: The patients who received dexamethasone and metoclopramide had significantly less nausea during the first 24 hours after chemotherapy was begun. Otherwise, there were no statistically significant differences in efficacy between the regimens. The incidence of drowsiness and increased appetite was higher in the group given dexamethasone and metoclopramide. Conclusions: For women with breast cancer who are being treated with cyclophosphamide, methotrexate, and fluorouracil, the efficacy of dexamethasone and metoclopramide in controlling nausea and vomiting equaled or exceeded that of ondansetron. (n Engl J Med 1993;328:1081-4.). [ABSTRACT FROM AUTHOR]