Local and distant recurrence after conservative management of "very low-risk" breast cancer are dependent events: a 10-year follow-up.

PURPOSE: To determine the risk factors associated with recurrence after breast-conserving treatments, and the relationship between occurrence of a local recurrence and subsequent distant metastases. METHODS AND MATERIALS: Among the 3697 patients with primary breast cancer treated at Institut Paoli-Calmettes Cancer Center, Marseille, between 1980 and 1995, we retrospectively analyzed 756 patients who had been treated with conservative surgery with uninvolved margins of excision, were node-negative, and had received uniform radiotherapy and no chemotherapy. One third of the patients received hormonal therapy via tamoxifen or surgical castration. The endpoints considered were local failures and distant metastases. All tumors were reviewed by our pathologists. The median follow-up for the 700 survivors was 62 months.
RESULTS: In the multivariate analysis, histological multifocality (p = 0.0076), peritumoral vessel invasion (p = 0.0215), and young age (p = 0.0245) were associated with an increased risk of local recurrences, whereas tumor size (p = 0.0013), young age (p = 0.003), and histological multifocality (p = 0.0414) were associated with an increased risk of distant metastases. Local recurrences and distant metastases had similar yearly-event probabilities. Median time to distant metastases was shorter after a local recurrence. Early timing of local recurrences did not mark a higher risk of distant metastases. Hazard of relapsing from distant metastases was 4.4 times higher after a local recurrence.
CONCLUSION: our results support the hypothesis that, in this subset of patients, local recurrences favor further dissemination of cancer cells. We are unable to clearly identify a group who would benefit from more aggressive local therapy.