Time trends in survival in young women with breast cancer in a population-based study: Are there estrogen receptor status differentials?

Abstract

85 Background: As mammography is not generally recommended to women under 40, it is reasonable to conclude that documented outcome improvements over time are attributable to treatment advances with screening playing a less important role. In order to determine the contribution of screening and treatment to improvements, we evaluated the odds of presenting with more advanced disease by time-period and examined the time-trends in outcome in a population-based cohort ≤50. We evaluated whether any outcomes differentials existed by ER status. Methods: Patients in SEER diagnosed with breast cancer were divided into 4 by year of diagnosis (1990-1994, 1995-1999, 2000-2004, 2005-2008). Patients were categorized into 2 age-groups: <40 and 40-50 years. Odds ratios for presenting with more advanced disease over the 4 time-periods were calculated for the 2 age-groups. Multivariate analysis was done to investigate the association of survival with time-period for the 2 age-groups by ER status. Results: 110,629 patient records were included. Patients 40-50 who were diagnosed in the 3 later time-periods (1995-1999, 2000-2004, 2005-2008) were more likely to have small tumors (≤2cm) compared with patients diagnosed in 1990-1994. Similarly, these patients were less likely to have larger tumors (≥3cm) comparing the 3 time-periods relative to 1990-1994. Conversely, patients <40 years had a higher odds of presenting with larger tumors (≥3cm) when the 3 later time-periods were compared to 1990-1994. In the ER positive patients, multivariate analysis showed that being diagnosed in the 3 later time-periods relative to 1990-1994 was associated with improved survival irrespective of age. In the ER negative cohort, those 40-50 years had a higher risk of death in the 3 later time-periods relative to 1990-1994; while there was a no effect of time-period on mortality for the younger age group of <40. Conclusions: Patients who are ER positive and between 40-50 years have had time-trend changes with improvements in breast cancer outcome and smaller tumors likely attributable to both screening and hormonal therapies. Patients who are <40 years and/or ER negative have not had improvements in breast cancer outcome.