Analysis of local recurrence after breast conservative treatment for invasive breast cancer: A single institution cohort

In a group of 900 patients treated for carcinoma of the breast, we evaluated patient-, tumour- and treatment-related parameters, predicting the success or failure of conservative treatment for invasive breast cancer. Thirty-one patients developed local recurrences which were detected within 0.1-12.1 years after treatment of the primary tumour (with a median of 6.2 years), providing a risk of 2% at 5 years and 9% at 10 years. The locally recurrent tumours and their original primary tumours of 28 patients could be retrieved from the pathology laboratory archives. These 28 tumours of the recurrence group (RG) were matched with tumours without local recurrence, the non-recurrence group, for age at time of diagnosis, duration of follow-up and T- and N-stage. The tumours were studied for type and grade of invasive tumour including the in situ component and involvement of surgical margins. In addition, the expression of cell-cycle proteins, p53, Ki-67 (MIB-1) and BCL-1, as well as HER-2/ neu oncoprotein, estrogen and progesterone receptor were investigated. We found a mean age at diagnosis for the RG of 50 years, and the mean age at time of diagnosis for the whole group of 900 patients was 56 years (p=0.003). Thirty-nine percent of the RG had a positive surgical margin, which was the case for only 18% in the control group (p=0.09). The presence of the in situ component was also correlated with increased local recurrence (p=0.022). Furthermore, local recurrence was also associated with a significantly increased occurrence of distant metastases (p=0.001). We conclude that breast conservative treatment is safe with a low local recurrence rate.