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

• Published in: Clinical breast cancer 2018-06, Vol.18 (3), p.246-253
• Main Authors: Rogoz, Bianca, Houzé de l'Aulnoit, Agathe, Duhamel, Alain, Houzé de l'Aulnoit, Denis
• Format: Article
• Language: English
• Subjects: Adult; Aged; Bone Neoplasms - mortality; Bone Neoplasms - secondary; Brain Neoplasms - mortality; Brain Neoplasms - secondary; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Disease-free interval; Disease-Free Survival; Female; Follow-Up Studies; France - epidemiology; Humans; Liver Neoplasms - mortality; Liver Neoplasms - secondary; Lymph Nodes; Lymphatic Metastasis - pathology; Middle Aged; Mortality - trends; Multivariate Analysis; Outcome; Prognosis; Prognostic factors of survival; Proportional Hazards Models; Site of metastasis; Time-varying effects
• ISSN: 1526-8209; 1938-0666
• DOI: 10.1016/j.clbc.2017.08.012

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. 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. 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). 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. 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.