The results of an overview of all randomized clinical trials has demonstrated that the use of adjuvant chemotherapy for younger or premenopausal women will reduce their annual odds of death by about 25%. The use of adjuvant tamoxifen in older or postmenopausal women, especially those with estrogen receptor-positive tumors, will have a similar effect. The absolute survival of patients with positive nodes at the end of 10 years will be between 8% and 10%. This does not mean necessarily that 8–10% of patients will be cured, and a more accurate description of the benefits of adjuvant therapy might be expressed as the average prolongation of life. This number is not as easily obtained. Differences in median survival between treated and untreated patients is approximately 2 years, and this might be taken as an approximation of the average increase in survival these patients will derive from adjuvant treatment. The proportional reduction in the odds of recurrence or death among women with negative nodes is identical to that of women with positive lymph nodes, but the absolute differences always will be greatest among those with the greatest risk of recurrence. Therefore, the use of adjuvant tamoxifen will result in a greater survival benefit for women with many positive nodes than for those with negative nodes.