INTRODUCTION: Changes in the American Joint Commission on Cancer staging for breast cancer occurred when the 5th Edition was updated to the 6th Edition. OBJECTIVE: To investigate how these changes affected stage and survival. METHODS: 3127 cases of breast cancer were restaged. RESULTS: Late stages increased from 27.7% to 38.1%. The five-year survival improved in Stage 2 (82.9-86.1%) and Stage 3 (50.6-59%). DISCUSSION: Stage shift leads to an erroneous impression that women are presenting with later stages and stage-specific survival is improving. CONCLUSION: Standardizing cancer staging is important when reporting stage and survival in different time periods.