Metastasis-free interval in breast cancer patients: Thirty-year trends and time dependency of prognostic factors. A retrospective analysis based on a single institution experience

摘要

Abstract Introduction Breast cancer remains the leading cause of cancer death in French women in spite of continuously improving management. The objectives of this study were to analyse trends in the metastasis-free interval over the past 30 years and to identify the prognostic factors of survival, while accounting for time dependency. Methods A total of 1613 patients diagnosed with invasive non-metastatic breast cancer at Saint Vincent de Paul Hospital, Lille, France between 1977 and 2013, were followed for outcome (metastasis-free interval). Cohort entry time delay, a continuous temporal covariate, was defined to assess improvement of outcome. Data were analysed using the Cox proportional hazards model and presented as hazard ratio (HR). Results Metastatic disease developed during follow-up in 446 (27.6%) patients. Cohort entry time delay exhibited strong independent prognostic value while accounting for multiple prognostic factors including: tumour size (HR?=?1.62, 95 %CI 1.37–1.91); rapid tumour growth (HR?=?1.59, 95%CI 1.17–2.16); lymph node ratio (HR?=?2.29, 95%CI 1.97–2.66); histological grade (grade 2 was significant only during the first 10 years after diagnosis, grade 3 and progesterone receptor status only during the first 5 years after diagnosis); and oestrogen receptor status (significant only during the first 8 years (HR?=?0.75, 95%CI 0.58–0.96)). Conclusion The current study showed an improvement in the prognosis of breast cancer patients over the past 30 years and pointed to the importance of evaluating covariates with time-varying effects.