Effects of a treatment gap during adjuvant chemotherapy in node-positive breast cancer: results of International Breast Cancer Study Group (IBCSG) Trials 13-93 and 14-93 Journal Articles uri icon

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  • BACKGROUND: The International Breast Cancer Study Group (IBCSG) conducted two complementary randomized trials to assess whether a treatment-free gap during adjuvant chemotherapy influenced outcome. PATIENTS AND METHODS: From 1993 to 1999, IBCSG Trials 13-93 and 14-93 enrolled 2215 premenopausal and postmenopausal women with axillary node-positive, operable breast cancer. All patients received cyclophosphamide (Cytoxan, C) plus either doxorubicin (Adriamycin, A) or epirubicin (E) for four courses followed immediately (No Gap) or after a 16-week delay (Gap) by classical cyclophosphamide, methotrexate, and fluorouracil (CMF) for three courses. The median follow-up was 7.7 years. RESULTS: The Gap and No-Gap groups had similar disease-free survival (DFS) and overall survival (OS). No identified subgroup showed a statistically significant difference, but exploratory subgroup analysis noted a trend towards decreased DFS for Gap compared with No Gap for women with estrogen receptor (ER)-negative tumors not receiving tamoxifen, especially evident during the first 2 years. CONCLUSIONS: A 16-week gap between adjuvant AC/EC and CMF provided no benefit and may have increased early recurrence rates in patients with ER-negative tumors.


  • Chasen, Martin
  • International Breast Cancer Study Group
  • Colleoni, Marco
  • Gelber, Shari
  • Simoncini, Edda
  • Pagani, Olivia
  • Gelber, Richard D
  • Price, Karen N
  • Castiglione-Gertsch, Monica
  • Coates, Alan S
  • Goldhirsch, Aron

publication date

  • July 2007

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