Which of the following statements most accurately reflects the findings of large overview analyses of clinical trials in which adjuvant chemotherapy for early-stage breast cancer was compared to a control group treated only with surgery?

B. Adjuvant therapy benefits all patients and is independent of age or node status.

DISCUSSION: An overview analysis (meta-analysis) examined nearly all randomized clinical trials in which chemotherapy after surgery was compared to surgery alone for treatment of early-stage breast cancer. This examination of the world's published literature revealed that the magnitude of benefit (the reduction in the odds of recurrence) from chemotherapy was relatively small and in the range of a 20% reduction in the chance of recurrence or death; however, this benefit extended to patients of all ages (young and older) and to both node-positive and node-negative patients. The value of adjuvant chemotherapy does not depend on the hormone receptor content of the cancer. It is useful to remember that a constant reduction in the odds of recurrence results in a higher absolute benefit as the prognosis worsens. If the chance of recurrence is 50% (for node-positive groups) the absolute reduction will be in the range of 10% or 15%. In contrast, if the recurrence rate is 10%, the absolute difference between treated and control groups will be less than 5%. This means that many patients need to be exposed to the risks and side effects of chemotherapy to benefit a very small number. This kind of thinking is currently used to decide who should receive adjuvant chemotherapy after primary treatment (mastectomy or lumpectomy).