Breast cancer is the most common cancer in women. Staging plays an important role in treatment planning. In the staging system published by AJCC in 2002, micrometastasis, the total number of metastatic lymph nodes, internal mammarian and supraclavicular lymph node metastases, and level III (apical) lymph node metastases were incorporated to the staging system. These modifications are likely to cause upstaging and changes in treatment plans, precisely in patients previously considered as stage II. This study aimed to investigate the outcomes of update in staging system in terms of mortality and morbidity. The records of 150 patients who underwent surgery for stage II breast cancer were retrospectively reviewed. The patients who were accepted as stage II according to the previous staging systems and planned to be treated accordingly were re-evaluated according to the newly updated staging system. Patients with and without stage change were compared in terms of mortality, local and systemic recurrence, and disease-free survival. We found that 41 (27.3%) of the patients who were accepted as stage II according to the previous staging systems had been upstaged in the new staging system. The relationship between stage migration and tumor diameter was statistically significant. Thirty-one patients (20.7%) had recurrence during follow-up. We found that most of the patients with recurrence (77.4%) had stage migration. There was a statistically significant relationship between apical lymph node involvement and recurrence. Updates in staging system of breast cancer cause stage migration in a significant proportion of patients with stage II breast cancer and are likely to lead to a change in treatment plans in some patients. Stage migration also has an impact on prognosis. In fact, recurrence is more common in patients with stage migration.
Breast cancer, cancer staging, stage migration, TNM, AJCC