Adjuvant systemic therapy for women with node-negative breast cancer. The Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer.

OBJECTIVE: To assist patients with node-negative breast cancer and their physicians in arriving at optimal decisions regarding treatment. EVIDENCE: Based on systematic literature review using primarily CANCERLIT from 1983 and MEDLINE from 1980 to September 1996. Nonsystematic review continued up to June 1997. RECOMMENDATIONS: Before deciding whether to use adjuvant systemic therapy, the prognosis without adjuvant therapy should be estimated. A patient's risk for recurrence can be categorized as low, intermediate or high on the basis of tumour size, histologic or nuclear grade, estrogen receptor (ER) status, and lymphatic and vascular invasion (LVI). For each individual, the choice of adjuvant therapy must take into account the potential benefits and possible side effects. These must be fully explained to each patient. Pre- and postmenopausal women who are at low risk of recurrence can be advised not to have adjuvant systemic treatment. Women at high risk should be advised to have adjuvant systemic therapy. Chemotherapy should be recommended for all premenopausal women (less than 50 years of age) and for postmenopausal women (50 years of age or older) with ER-negative tumours. Tamoxifen should be recommended as first choice for postmenopausal women with ER-positive tumours. For this last group of patients, it is possible that further benefit may be obtained from the addition of chemotherapy to tamoxifen. For women at intermediate risk with ER-positive tumours, tamoxifen should normally be the first choice. For those who decline tamoxifen, chemotherapy may be considered. For most patients over 70 years of age who are at high risk, tamoxifen is recommended regardless of ER status. For some who are in robust good health, chemotherapy is a valid option. There are 2 recommended chemotherapy regimens: (1) 6 cycles of cyclophosphamide, methotrexate and 5-fluorouracil (CMF); (2) 4 cycles of Adriamycin and cyclophosphamide (AC). Tamoxifen should normally be administered daily for 5 years. Patients should be offered the opportunity of participating in therapeutic trials whenever possible. VALIDATION: The authors' original text was revised successively by a writing committee, expert primary reviewers, secondary reviewers, and by the Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer. The final document reflects a substantial consensus of all these contributors.