Adjuvant therapy of node-negative breast cancer

OBJECTIVE: To present the controversies regarding adjuvant cytotoxic chemotherapy or hormonal therapy in patients with node-negative breast cancer, and to evaluate the use of prognostic factors in identifying patients with node-negative breast cancer who will benefit from adjuvant therapy. DATA SOURCE: A MEDLINE search was performed to identify pertinent primary literature and review articles. Articles also were identified through Current Contents, textbooks, and bibliographies of selected articles. DATA EXTRACTION: The most recent clinical trials that evaluated cytotoxic chemotherapy or hormonal therapy in patients with node-negative breast cancer were chosen. Recent review articles and clinical trials that analyzed prognostic factors also were evaluated. DATA SYNTHESIS: The treatment of patients with node-negative breast cancer remains controversial. Approximately 60-80% of patients with this diagnosis will be alive 10 years after initial treatment without adjuvant therapy. The use of chemotherapy or hormonal therapy in node-negative disease increased after the 1988 National Cancer Institute Clinical Alert. Since that time, the research in node-negative breast cancer has focused on identifying prognostic factors and evaluating new treatment regimens. It is hoped that prognostic factors will help direct treatment decisions by identifying subgroups of patients who may benefit from adjuvant therapy. Prognostic factors currently being evaluated include tumor size, hormonal receptors, ploidy status, S-phase fraction, and cathepsin D. CONCLUSIONS: Many patients with node-negative breast cancer will be cured by local therapy alone. Even so, up to 58% of node-negative patients may develop recurrent disease. Reduction of breast cancer recurrence in patients with node-negative breast cancer has been documented as a result of adjuvant chemotherapy or tamoxifen. Of utmost priority is the identification of patients with node-negative breast cancer at highest risk for recurrence so that they may receive appropriate adjuvant therapy with curative intent, while sparing patients at lower risk for recurrence the toxic effects and financial burden incurred by unnecessary adjuvant treatment.