Aims of the study: To determine the risk factors for local and distant failure in node-negative breast cancer treated with breast-conservative surgery and radiotherapy and to determine the relationship between these two events.
Material and methods: We retrospectively selected 908 patients who received conservative surgery and radiotherapy but no chemotherapy between 1980 and 1995, for a node-negative breast cancer. Patients were divided in two groups according to the status of the margins of resection. All pathology specimens were reviewed.
Results: In case of negative margins, the risk factors for local recurrences picked up by the Cox model were histologic multifocality (P = 0.0076), peritumoral vessel invasion (P = 0.021) and age < or = 40 years (P = 0.024), and in case of involved margins, negative oestrogen receptors (P = 0.0012), histologic multifocality (P = 0.0028), and absence of hormonal therapy (P = 0.017). The 10-year local recurrence rate was 18% in case of negative margins and 29% in case of involved margins, although in the latter case patients received high-dose adjuvant radiotherapy. Accordingly, the 10-year distant failure rates were 16% and 27%, respectively. Many arguments suggest that local and distant failures are closely related.
Conclusion: Patients with histologic multifocality or positive margins are at high risk of local failure and then of distant failure, and require a more aggressive initial treatment.