Thirty-Year Trends of Survival and Time-Varying Effects of Prognostic Factors in Patients With Metastatic Breast Cancer A Single Institution Experience

In our study we aimed to detect a time trend of survival of metastatic breast cancer patients over the past 30 years and account for time-varying effects of the prognostic factors. Our cohort was represented by 446 breast cancer patients diagnosed between 1977 and 2013 who developed metastatic disease after a disease-free interval longer than 3 months. We detected a monotonic time trend of improvement in prognosis of metastatic breast cancer patients and we identified 3 prognostic factors with time-varying effects. Background: Metastatic breast cancer is generally considered an incurable disease. In our study we aimed to detect a time trend of survival over the past 30 years and account for time-varying effects of the prognostic factors. Patients and Methods: A total of 446 patients diagnosed with breast cancer at Saint Vincent de Paul Hospital, Lille, France between 1977 and 2013 who developed metastatic disease after a disease-free interval longer than 3 months and were followed-up for outcome. Data were analyzed using the Cox proportional hazards model and presented as hazard ratios (HRs). Results: A monotonic time trend of survival was detected: a 2.6% lower risk of death for each increasing year over the past 30 years. Three prognostic factors had time-varying effects; the liver first metastasis (HR during the first 16 months of follow-up: 2.26; 95% confidence interval [CI], 1.65-3.11), the bone first metastasis (HR during the first 24 months of follow-up: 0.56; 95% CI, 0.43-0.74), and the disease-free interval (HR during the first 16 months of follow-up: 0.90; 95% CI, 0.85-0.95). The brain first metastasis, multiple first metastases, the lymph node ratio, and estrogen receptor status had a constant effect over time. Conclusion: In our study we detected a constant time trend of improvement in prognosis of metastatic breast cancer patients over the past 30 years and identified prognostic factors with time-varying effects. (C) 2017 Elsevier Inc. All rights reserved.