Patterns of tumor relapse following mastectomy and adjuvant systemic therapy in patients with axillary lymph node-positive breast cancer. Impact of clinical, histopathologic, and flow cytometric factors.

BACKGROUND

This analysis was conducted to evaluate the impact of selected clinical, histopathologic, and flow cytometric factors on sites of initial tumor relapse after postmastectomy adjuvant systemic therapy.

METHODS

Five hundred sixty-four patients with axillary node-positive breast cancer were entered in two prospectively randomized trials and received cyclophosphamide, 5-fluorouracil and prednisone with or without tamoxifen as sole adjuvant therapy. These patients were studied to assess the risk of locoregional recurrence and to identify factors that might predict tumor relapse site.

RESULTS

With a median follow-up of 9.3 years, the 8-year cumulative incidences of initial locoregional or distant relapse were 20% and 35%, respectively. Pathologic tumor stage, estrogen receptor content, and number of involved axillary nodes were independent predictive factors for an increased risk of locoregional recurrence. With the exception of tumor stage, these factors also were associated with an increased risk of distant relapse so that tumor stage (T3a) remained the sole factor predictive of increased relative risk for initial locoregional (versus distant) recurrence in patients with tumor progression. Clinical and flow cytometric factors were not predictive of initial locoregional or distant relapse.

CONCLUSIONS

Exploratory data analysis of two prospective trials of postmastectomy adjuvant systemic therapy has demonstrated a significant risk for initial isolated locoregional recurrence in certain patients with node-positive breast cancer. The benefit of improved locoregional tumor control in appropriately selected patients with axillary node-positive breast cancer who receive adjuvant systemic therapy requires additional investigation.