Conservative treatment versus mastectomy in early breast cancer: patterns of failure with 15 years of follow-up data. Institut Gustave-Roussy Breast Cancer Group.

Purposes: A randomized trial was conducted to compare tumorectomy and breast irradiation with modified radical mastectomy. We have analyzed the patterns of failure in each arm of the trial and the prognostic factors that have an independent effect on treatment failures and overall survival.
Patients and Methods: The trial included 179 patients with breast cancer of up to 20 mm in diameter at macroscopic examination. Eighty-eight patients had conservative management and 91 a mastectomy. All patients had axillary dissection with frozen-section examination. For patients with positive axillary nodes (N+), a second randomization was performed: lymph node irradiation versus no further regional treatment. Patterns of failure were determined by a competing-risk approach and multivariate analysis. A prognostic-score was determined by multivariate analysis.
Results: Overall survival, distant metastasis, contralateral breast cancer, new primary malignancy, and locoregional recurrence rates were not significantly different between the two surgical groups, or between lymph node irradiation groups. Most recurrences appeared during the first 10 years. Three distinct prognostic groups were determined taking into account age, tumor size, histologic grading, and number of positive axillary nodes.
Conclusion: Long-term results support conservative treatment with limited surgery and systematic breast irradiation as a safe procedure for the management of small breast cancers. Four easily obtainable clinical and histologic factors may be combined in a prognostic score that is highly predictive of overall and event-free survival.