Local Recurrence after Breast Cancer Affects Specific Survival Differently according to Patient Age

Abstract

Young age is known to be an independent factor for developing local recurrence (LR) in breast cancer patients. It has also been shown that the occurrence of LR negatively affects patient outcome, especially if LR occurs within 3 years after treatment of the primary tumour. The question whether the impact of LR on patient outcome differs according to the patient's age has not been addressed before. The purpose of the present study is to investigate cancer-specific survival (CSS) as well as overall survival after LR in young patients (<50 years old) and to compare it to older patients. The age cut-off level was taken as 50 to avoid strong imbalance in patient numbers between the 2 groups. Between 1974 and 2003, 2,130 breast cancer patients were treated with conservative surgery and axillary dissection. All of them received post-operative radiotherapy. Adjuvant chemo- and/or hormonal therapy was given according to the prognostic factors and the treatment policy at the time of diagnosis. Only biopsy-confirmed ipsilateral LRs were taken into account. Early LRs were those observed within 36 months after surgery, and late LRs were those which occurred thereafter. The median follow-up was 100 months. Survival analysis was conducted with the Kaplan-Meier method. The median age was 59 years. There were 472 patients aged <50 years versus 1,658 older patients. Pathological tumour size, hormone receptor status and lymph node involvement were evenly distributed in the 2 groups. The 5- and 10-year CSS was 92.3 and 83.9% in young patients, and 94.4 and 87.6% in older patients (p = 0.061), respectively. Overall, 200 LRs were observed; 52 of them (26%) were early LRs. The rate of LR was significantly higher in young patients: at 5 years, it was 10.5 versus 3.7% in patients ≥50 years; the respective rates at 10 years were 17.8 and 8.8% (p < 0.0001). The 5- and 10-year CSS in patients who developed LR was 86.8 and 76.0%, versus 94.7 and 88.2% in patients who did not develop LR (p < 0.0001). The 5-year CSS after LR in young and older patients was 77.6 and 65.7%, respectively (p = 0.028). Although young patients experience more LR than older ones, once LR occurs, young patients have a better outcome than the others. Possible hypotheses are: (1) more aggressive treatment in young patients after LR; (2) the treatment is better sustained in young patients; (3) biological differences in the characteristics of LR.