Racial differences in breast cancer survival in women under age 60

Abstract

There is a known difference in breast cancer survival between races in the US for which several factors such as social, lifestyle and genetic factors may be relevant. This is a retrospective study among women entitled to free treatment in the US department of defense health care system. Within this group, we investigated the temporal trend of absolute survival of 13,793 of White and African American aged 20-59 years and diagnosed between 1980 and 1999 with breast cancer. There is a 3% overall improvement in survival in whites which can be explained by an earlier detection, and a two percent decrease in AA with a distinct pattern by age group. In the 40-49 year age group, the survival in white increases from 84.5% in the year 1980-1984 to 87.4 % in the year 1995-1999, in AA we estimate a decrease from 79.7% to 78.5%. When accounting for stage at diagnosis a slight reduction in survival in whites and a strong reduction in AA indicates a significant interaction between race and calendar period. The differences in survival patterns between blacks and whites are mainly caused by breast cancer and not by other causes. The gap in survival which strongly increased with calendar period cannot be explained by unequal access to health care. Possible explanations include a lower participation of early detection programs for breast cancer in AA and an increasing prevalence of obesity over time which is more pronounced in AA than in whites.