Long-term locoregional recurrence in patients treated for breast cancer.

Background/purpose: Locoregional control in breast cancer is a fundamental part of treatment and determinant for survival outcomes. It has been reported that most locoregional recurrence (LRR) events occur in the first 5 years after treatment. However, LRR continue to occur after this timeline, with unclear risk factors and unknown survival impact.

Methods: Retrospective singe-centered cohort of patients treated for primary breast cancer, between January 2002 and December 2004. Primary outcome was LRR; secondary outcomes were overall survival (OS), disease-free survival (DFS), and predictive factors for LRR.

Results: This analysis included 1001 patients, of which 959 (95%) had invasive carcinoma. A mastectomy was performed in 501 (50%) and 500 (50%) had breast conservative surgery (BCS). Median follow-up time was 197 [Inter-quartile range (IQR) 96-211] months. Global LRR rate was 7.6%, with median time to recurrence of 45 [IQR 21-91] months. There was no difference in LRR rate after mastectomy vs BCS, adjusted to tumor stage (p > 0.05). The 10-year OS and DFS rates were 68.4 and 77.8%, respectively. Factors associated with LRR were metastatic axillary lymph nodes and high histologic grade (p < 0.05). Estrogen-negative (ER) tumors had higher LRR rates than ER-positive tumors in the first 5 years (p < 0.05); but no difference was observed with longer follow-up (p > 0.05). LRR was associated with OS (p < 0.05).

Discussion And Conclusions: Global LRR in this cohort was 7.6% (with over 16 years of follow-up). LRR associates with decreased OS. Time to LRR varies significantly with tumor biology, supporting differentiation of follow-up regimens.