A Randomized Trial of Letrozole in Postmenopausal Women after Five Years of Tamoxifen Therapy for Early-Stage Breast Cancer

• Published in: The New England journal of medicine Vol. 349; no. 19; pp. 1793 - 1802
• Main Authors: Goss, Paul E, Ingle, James N, Martino, Silvana, Robert, Nicholas J, Muss, Hyman B, Piccart, Martine J, Castiglione, Monica, Tu, Dongsheng, Shepherd, Lois E, Pritchard, Kathleen I, Livingston, Robert B, Davidson, Nancy E, Norton, Larry, Perez, Edith A, Abrams, Jeffrey S, Therasse, Patrick, Palmer, Michael J, Pater, Joseph L
• Format: Journal Article
• Language: English
• Published: United States Massachusetts Medical Society 06-11-2003
• Subjects: Adult; Aged; Antineoplastic Agents - therapeutic use; Antineoplastic Agents, Hormonal - therapeutic use; Aromatase Inhibitors; Bone density; Breast cancer; Breast Neoplasms - drug therapy; Cancer therapies; Chemotherapy; Chemotherapy, Adjuvant; Double-Blind Method; Enzyme Inhibitors - therapeutic use; Female; Humans; Middle Aged; Neoplasms, Hormone-Dependent - drug therapy; Nitriles - therapeutic use; Postmenopause; Quality of Life; Survival Analysis; Tamoxifen - therapeutic use; Triazoles - therapeutic use; Womens health
• ISSN: 0028-4793; 1533-4406
• DOI: 10.1056/NEJMoa032312

Postmenopausal women with early breast cancer who have undergone successful initial therapy receive five years of treatment with tamoxifen, an antagonist of the estrogen receptor. This placebo-controlled trial investigated whether the administration of letrozole, an aromatase inhibitor, after five years of tamoxifen therapy is beneficial. The trial was stopped because of a statistically significant reduction in the rate of breast-cancer–related events in the letrozole group as compared with the placebo group.
This trial was stopped after an interim analysis.
The risk of a recurrence of breast cancer continues for an indefinite period after surgery, radiation, and medical therapy.
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,
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Since the growth of breast cancer depends on the action of estrogen,
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long-term reductions in the risk of recurrence have been achieved by antagonizing the activity of estrogen with the selective estrogen-receptor modulator tamoxifen in women with hormone-receptor–positive tumors.
1
,
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The postoperative administration of tamoxifen for five years reduces the risk of recurrence by 47 percent and reduces the risk of death by 26 percent.
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,
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However, in a trial conducted by the National Surgical Adjuvant Breast and Bowel Project . . .