Which of the following statement(s) is/are true concerning adjuvant systemic therapy?

a. Adjuvant tamoxifen in post-menopausal, node-positive, ER-positive women is equivalent to cytotoxic chemotherapy

Adjuvant tamoxifen leads to a prolonged disease-free interval in post-menopausal ER-positive women with histologically positive nodes and in pre-menopausal and post-menopausal ER-positive women with negative nodes. Because of similar results and, because tamoxifen is generally less toxic than chemotherapy, this treatment is the treatment of choice for post-menopausal, node-positive, ER-positive women. CMF (cyclophosphamide, methotrexate, and 5-fluorouracil) is associated with both a longer disease-free survival and overall survival time in pre-menopausal patients with positive lymph nodes. In post-menopausal women with positive nodes, there is an improved disease-free survival, but there is no significant difference in overall survival. Several trials of adjuvant chemotherapy with CMF or related regimens have been conducted in node-negative patients. The early results of all of these trials have been similar: disease-free survival is definitely improved with adjuvant chemotherapy. These studies are definitely not mature enough to draw definitive conclusions regarding overall survival. Therefore, the National Cancer Institute has recommended the use of adjuvant chemotherapy for all patients with tumors large enough to have hormonal receptor levels measured.