P1-08-03: Huge Improvement in Relapse-Free Breast Cancer Survival over the Last 25 Years.

Abstract

Abstract Introduction The purpose of this study was to evaluate the dwindling risk of relapse in breast cancer patients treated with curative intent since the 1970s. Patients and methods 8570 women diagnosed with invasive breast cancer in 2003 or 2004 were compared with 307 consecutively diagnosed patients with invasive breast cancer between 1972 and 1986 in the Netherlands. Five-year overall survival and 5-year risk of relapse, i.e. second primary breast cancer, locoregional recurrence or distant metastasis, were calculated using the Kaplan-Meier method. Multivariable Cox-proportional hazards modelling was applied to correct the period-specific risk of relapse for tumour size, lymph node involvement and age at diagnosis. Results Median (range) age at diagnosis was 52 years (27-82 years) in 1972–1986 and 58 years (20-96 years) in 2003–2004. Patients diagnosed in 1972–1986 had a larger tumour size and similar nodal involvement as compared to patients diagnosed in 2003–2004. In 2003–2004 more women were treated with breast conserving surgery, chemotherapy, and hormonal therapy as compared to 1972–1986. The 5-year overall survival rate increased from 71% (95% CI: 65% — 76%) in the period 1972–1986 to 85% (95% CI: 84% — 85%) in the years 2003–2004. Five-year risk of any relapse decreased from 37% to 16% across the calendar years (table 1). This decrease was observed for the risk of locoregional recurrence and the risk of distant metastasis (table 1). Risk of second primary breast cancer was similar for both periods of diagnosis (table 1). After adjustment for tumour size, nodal status and age at diagnosis the decrease in risk of relapse remained significant for patients diagnosed in 2003–2004 compared to 1972–1986 (HR= 0.5, 95% CI: 0.4 - 0.6). Conclusion Over the last decades, the risk of breast cancer relapse has tremendously decreased, also after adjustment for tumour stage and age at diagnosis. The improved prognosis can be explained by the more often administered and intensified systemic treatment procedures and, further, by an earlier detection. The similar nodal stage probably resulted from stage migration caused by a more thoroughly performed lymph node staging in 2003–2004 compared to 1972–1986. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-08-03.