Abstract P6-12-01: Survival of women with inflammatory breast cancer: A large population based study

Abstract

Abstract Background The introduction of efficacious polychemotherapy regimens and targeted biologicals has contributed to significant improvements in survival of women with breast cancer. However, our group has previously reported that women with inflammatory breast cancer (IBC) continue to have worse outcome compared to those with non-inflammatory breast cancer. We undertook this population based study to see if there have been improvements in survival among women with stage III IBC, over time. Methods We searched the Surveillance, Epidemiology and End Results Registry to identify female patients diagnosed with stage III IBC between 1990 and 2010. Follow up cut off was December 31st 2010. Patients were defined as having IBC according to the AJCC 6th edition criteria. Patients were divided into 4 groups according to year of diagnosis: 1990-1995, 1996-2000, 2001-2005 and 2006-2010. Breast cancer specific survival (BCSS) was estimated using the Kaplan-Meier method and compared across groups using the log rank statistic. Cox models were then fitted to determine the association of year of diagnosis and BCSS after adjusting for patient and tumor characteristics. Results 7,679 patients with IBC were identified of whom 1,084 patients (14.1%) were diagnosed between 1990-1995, 1,614 patients (21.0%) between 1996 -2000, 2,683 patients (34.9%) between 2001-2005 and 2,298 patients (29.9%) between 2006-2010. Median follow-up was 30 months. The 2-year BCSS for the whole cohort was 71%. 2-year BCSS were 62%, 67%, 72%, and 76% for patients diagnosed between 1990-1995, 1996-2000, 2001-2005 and 2006-2010 respectively (p<0.0001). The absolute increase in 2-year BCSS over the immediately preceding time period were 5%, 5%, and 4%, respectively. Significant improvements in survival over time were also observed among patients younger and older than age 35 years. In a multivariable cox regression analysis increasing year of diagnosis (modeled as a continuous variable) was associated with decreasing risk of death from breast cancer (HR = 0.98, 95% CI: 0.97 – 0.99, P < 0.0001). Conclusion There has been a significant improvement in survival of patients diagnosed with IBC over a two decade time span in this large population based study. This suggests that therapeutic strategies researched and evolved in the context of non inflammatory breast cancer have also had a positive impact in women with IBC. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-01.