This study attempts to address whether adjuvant therapy should be used in patients with small tumors. This is a retrospective analysis of the clinical outcome of patients with tumors =1 cm in diameter and LNN disease who were recruited to several NSABP trials between 1976 and 1991. However, even the cumulative number of patients remains too small to allow definitive conclusions. A thoughtful review of the limitations of this study are outlined in an accompanying editorial by Lippman and Hayes (see Additional information). The authors address the risk/benefit issue with respect to the use of chemotherapy in a subgroup of patients who would otherwise be expected to have a very good prognosis. They discuss the important issue of absolute prognosis; it would be expected that giving chemotherapy to a patient with a 95% chance of survival after surgery alone would increase her absolute odds of survival by no more than 2%. The editorial also highlights the miniscule numbers of patients with T1a (=5 mm) tumors and tumors 6-9 mm included in the outcome analysis and it is particularly in patients with tumors in this size range where the risks of chemotherapy may indeed exceed the benefits.
The authors conclude that chemotherapy and/or tamoxifen 'should be considered' for all patients with tumors < 1cm and LNN disease. However, there was no difference in overall survival between ER-negative patients treated with surgery alone versus those treated with surgery and chemotherapy (93% and 91%, P = 0.65). For ER-positive patients, survival differed only for those patients treated with tamoxifen versus those treated with tamoxifen and other chemotherapy (92% and 97% respectively, P = 0.01). While there is little doubt that chemotherapy is efficacious in this group of patients, it remains debatable as to whether the benefits of chemotherapy outweigh the risks, particularly in patients with T1a tumors where the event-free survival may be greater than 95%.