Adjuvant systemic therapy for patients with node-negative tumors

Early adjuvant therapy studies, especially adjuvant chemotherapy studies, were performed almost exclusively on patients with histologically involved axillary lymph nodes ("node-positive" patients). These therapies were restricted to this group of patients because the toxicities of adjuvant therapy were believed too great to justify its use in patients with a very good prognosis until its benefits were fully established. However, after it was demonstrated that adjuvant therapy can significantly prolong the disease-free survival of almost all groups of node-positive patients and the overall survival of some patient subsets, adjuvant therapy trials specifically designed for patients without histologically involved lymph nodes ("node-negative" patients) were initiated. Results from some of the largest of these second generation trials were recently published, and the early results from these studies have generated new questions. For example, will the mature results from these studies be nearly identical to the results seen in node-positive patients, or will node-negative patients derive greater benefits from adjuvant therapy? Is it possible that adjuvant therapy will "cure" node-negative patients but not node-positive patients? (Cure is defined here as an effect of therapy that returns a patient to the life expectancy she might have had if she had never been diagnosed with breast cancer). Is it possible that the added years of life from adjuvant therapy or that the number of node-negative patients who benefit are so small that these benefits will be outweighed by delayed toxicities that appear in patients who might have been cured even without adjuvant therapy? At present the available data to answer these questions definitely are either contradictory or nonexistent.