Impact of adjuvant chemotherapy in breast cancer on response to tamoxifen at relapse

A series of 105 patients with operable breast cancer previously entered in the WMOA adjuvant therapy trials were reviewed in order to assess methods of treatment on relapse and subsequent patterns of relapse and survival, related to previous adjuvant therapy. Tamoxifen was the predominant medical therapy offered on relapse. Unexpectedly, analysis of the relapse and survival data for these hormonetreated patients suggested that prior adjuvant therapy negatively influenced response to tamoxifen, with overall survival of treated and control patients being identical. Although not statistically significant, possible explanations of this trend have been explored.