Local recurrence following breast-conserving treatment in women aged 40 years or younger: trends in risk and the impact on prognosis in a population-based cohort of 1143 patients

Aim: To evaluate trends in the risk of local recurrences after breast-conserving treatment (BCT) and to examine the impact of local recurrence (LR) on distant relapse-free survival in a large, population-based cohort of women aged ≤40 years with early-stage breast cancer.

Methods: All women (n=1143) aged ≤40 years with early-stage (pT1-2/cT1-2, N0-2, M0) breast cancer who underwent BCT in the south of the Netherlands between 1988 and 2010 were included. BCT consisted of local excision of the tumour followed by irradiation of the breast.

Results: After a median follow-up of 8.5 (0.1-24.6)years, 176 patients had developed an isolated LR. The 5-year LR-rate for the subgroups treated in the periods 1988-1998, 1999-2005 and 2006-2010 were 9.8% (95% confidence interval (CI) 7.1-12.5), 5.9% (95% CI 3.2-8.6) and 3.3% (95% CI 0.6-6.0), respectively (p=0.006). In a multivariate analysis, adjuvant systemic treatment was associated with a reduced risk of LR of almost 60% (hazard ratio (HR) 0.42; 95%CI 0.28-0.60; p<0.0001). Patients who experienced an early isolated LR (≤5 years after BCT) had a worse distant relapse-free survival compared to patients without an early LR (HR 1.83; 95% CI 1.27-2.64; p=0.001). Late local recurrences did not negatively affect distant relapse-free survival (HR 1.24; 95% CI 0.74-2.08; p=0.407).

Conclusion: Local control after BCT improved significantly over time and appeared to be closely related to the increased use and effectiveness of systemic therapy. These recent results underline the safety of BCT for young women with early-stage breast cancer.