Contemporary risks of local and regional recurrence and contralateral breast cancer in patients treated for primary breast cancer

Introduction Breast cancer treatment has evolved extensively over the past two decades with a shift towards less invasive local treatment and increased systemic treatment. The present study aimed to investigate the rates of local (LR) and regional (RR) recurrence and contralateral breast cancer (CBC), evaluating the influence of contributing factors. Materials and methods We selected all female patients operated for unilateral primary breast cancer (anyTN, M0) between 2003 and 2008 from the Netherlands Cancer Registry. The 5-year risks of developing LR, RR and CBC were estimated using Kaplan-Meier statistics. The influence of various patient, tumour and treatment characteristics was subsequently assessed in multivariable analyses. Results A total of 52,626 patients were identified. The rates of LR, RR and CBC were 2.7%, 1.5% and 2.9%, respectively. The rates of LR and RR decreased significantly over time in the period 2003-2008, from 3.2% to 2.4% for LR and 1.8 to 1.3% for RR, both becoming lower than the risk of CBC of 2.8%. Multivariable analysis showed that age, tumour size, lymph node involvement, tumour histologic type, grade and hormone receptor status were significant prognosticators for LR and RR, but not for CBC. A trend towards a beneficial effect of breast conserving surgery on LR and RR was seen, while systemic therapy proved to have a protective effect on all three end-points. Conclusions In breast cancer patients treated between 2003 and 2008 locoregional recurrence rates decreased and have ended up lower than the risk of developing CBC.