Falling Stars: The Patchwork Quilt Of The Falling Death Rates From Breast Cancer In The USA
Prior studies have shown that breast cancer incidence has increased from 1999 to 2018. These authors from the Division of Cancer Prevention and Control decided to look at the mortality from breast cancer during this era from 1999 to 2018. As you may be aware breast cancer is the most common cancer diagnosis among women in the second most common cause of cancer deaths among women in the United States, the first being lung cancer. Breast cancer is however the leading cause of cancer deaths in some racial and ethnic groups including non-Hispanic black women. Although breast cancer death rates have been on the decline beginning in the 1980s, there was also the divergence and trends in breast cancer mortality between black and white women. Although the divergence is somewhat stabilized, death rates are still higher among black womenA previous study found that despite a lower incidence rate, black women had a 41% higher death rate. (Centers for Disease Control and Prevention. Vital signs. Racial disparities in breast cancer severity-United States 2005 – 2009. 2012; 61 (45): 922 – 926). Breast cancer characteristics contribute to differences in breast cancer mortality between black and white women. One study showed that insurance status accounts for more than one-third of the survival disparity and non-elderly women, more than the percentage from tumor characteristics (JamaL, et al., J Clin Oncol: 14-24). In this study age groups are categorized into three different groups, 25 to 44, 45 to 64, and greater than or equal to 65 years of age. Using census data states were grouped into four regions: Northeast Midwest South and West.
From 1999 to 2020 there were 909,488 deaths attributed to breast cancer among women. On average, breast cancer death rates decreased by 1.6% per year from 1999 to 2020. Rates decreased by 1.3% per year from 1999 to 2002, 2.2% per year from 2002 to 2008, and 1.4% per year from 2008 to 2020. Although among non-Hispanic white women breast cancer death rates decreased 1.6% per year on average from 1999 to 2020 rates decreased by only 0.4% per year on average among non-Hispanic Asian or Pacific Islander women. However, non-Hispanic black women had the highest absolute change in rate between 1999 and 2020 (a decrease of 9.3%!)
Women aged 45 to 64 had the largest decrease in breast cancer death rates, with a decrease of 2.0% per year on average decreasing 2.7% per year between 2001 and 2008 and 1.8% per year between 2008 and 2020. Women aged 65 or older at the smallest decrease in breast cancer death rates from 1999 to 2020 with a decrease of 1.4% per year on average. Among women 25 to 44, breast cancer death rates decreased by 1.5% per year on average.
Using the US census regions, women who lived in the Northeast at the time of death at the largest decrease in death rates attributed to breast cancer (2.1% per year on average) from 1999 to 2020. The women who lived in the South at the time of death had the smallest decrease in death rates attributed to breast cancer (1.4% per year on average). Though it is clear that the death rate from breast cancer has been falling for some time now, ethnicity and the census regions are clearly impacting the overall results. Moreover, the incidence of breast cancer and the time of diagnosis clearly impact later mortality. There are clearly differences in reproductive patterns, postmenopausal hormone use, and mammographic screening intervals throughout the US census regions. These recommendations could clearly impact overall mortality based on the census regions. Hormone replacement therapy taken during menopause for at least five years may have some impact on the risk of breast cancer. Prior studies have associated the decrease observed in breast cancer incidence specifically in the early 2000’s to be temporarily related to the first report of the women’s health initiative in the ensuing drop in the use of hormone replacement therapy among postmenopausal women in the United States. Results of this study indicate that breast cancer death rates decreased the most from 2002 and 2008 which corresponds to this period. Rapid declines in the early 2000’s may in part reflect both dissemination of treatment advances and declines in hormone receptor-positive incidence following the Women’s Health Initiative article.
Non-Hispanic Asian or Pacific Islander women in the smallest decline in death rates attributed to breast cancer. From 2008 to 2015 breast cancer screening increased slightly among Hispanic women, declining more than 10% in some groups including Asian women. Additional analyses of breast cancer incidence including stage at diagnosis and mortality trends among Asian or Pacific Islander women may help explain the slower decline in mortality.
Summary
The breast cancer continues to fall in the United States. The fall however is not even as it is more apparent in the non-Hispanic white population compared to Hispanic, Asian and Pacific Islander women. The fall is also occurring in the black population despite its continued increase in mortality compared to other ethnic groups. It is likely that a later stage of diagnosis may be impacting the slope of fall in mortality seen in other ethnic groups. Similar pre-diagnostic factors may be at play when considering U.S. Census regions.
Dr. Alan Stolier, MD, FACS, clinical breast oncologist, shares his expert medical perspective with a series of educational and scientific articles.