Study: Disparities in research impact breast screening guidelines

IN-DEPTH REVIEW OF RESEARCH

Study background:

Professional and governmental organizations differ in their recommendations for when women of average risk should begin annual breast cancer screening. While the USPTSF recommends screening beginning at age 50, the American Cancer Society recommends beginning at age 45, and the American College of Obstetricians and Gynecologists and the American College of Radiology recommends annual screening beginning at age 40. 

Currently, legislation known as the PALS Act requires health insurance companies to cover annual mammograms for women beginning at age 40 with no out-of-pocket costs. Recently the act was extended until January 31, 2019. 

Researchers of this study wanted to know:

whether current USPSTF breast cancer screening recommendations reflect age-specific patterns based on race.

Study findings:  

The authors report 2 distinct distributions of patterns at age of diagnosis.  White patients’ diagnoses peak in their 60s, while nonwhite patients peak in their 40s.  Compared to white patients, a higher proportion of nonwhite patients present with more advanced disease.

For the 747,763 female patients included in this study:

• Overall, median age at diagnosis was 58 years, but varied among racial groups:
  • White women: 59 years
  • Hispanic American women: 55
  • African American women: 56 years
  • Asian American women: 56 years
• A higher proportion of patients with breast cancer were diagnosed before age 50 among nonwhite patients compared to white patients:
  • African Americans: 31%
  • Hispanic Americans: 35%
  • Asian Americans: 32.8%  
  • White Americans: 23.6%
• A higher proportion of African and Hispanic American patients presented with advanced (regional or distant) disease (46.6 % and 43% respectively, than white or Asian American patients (37.1% and 35.6% respectively).

Study design:

In a letter published on March 7th, 2018 in the Journal of the American Medical Association, Stapleton and colleagues analyzed data in the Surveillance, Epidemiology and End Results (SEER) Program database collected between January 1, 1973 and December 31, 2010.  Female patients aged 40 to 75 years with malignant breast cancers were included.  Primary endpoints were age and stage at breast cancer diagnosis across all racial groups.

Limitations:

The main limitation to this study is that despite being the largest cancer database in the U.S., SEER does not capture all of the U.S. population.

Conclusions:

Though women of color were diagnosed with breast cancer at a younger age than white women, the age at which the USPSTF recommends regular mammogram screenings is based on research done on white women. This is one example of a larger bias in scientific research-most research is done in predominantly white populations. This bias affects science, medicine, and ultimately may affect a women’s health.

The findings of this new study challenge established screening recommendations, currently based on predominantly white women, and provide evidence that race-based breast cancer screening recommendations should be considered.  The study authors suggest that age-based screening guidelines that do not account for race and may adversely affect nonwhite women in the U.S.  It is important to note that the authors recommend selective increases in breast cancer screening among nonwhite women, but they do not suggest increased screening across the entire U.S. population.

Of particular note, this April, the American College of Radiology (ACR) and Society of Breast Imaging (SBI) breast cancer screening guidelines were the first to recognize that African-American women are at high risk for the disease and should be screened accordingly. The ACR and SBI guidelines now recommend a risk assessment at age 30 for all women to see if screening earlier than age 40 is needed. Both groups now also recommend that women who were previously diagnosed with breast cancer be screened with magnetic resonance imaging (MRI).  The ACR and SBI continue to recommend that women at average breast cancer risk begin screening at age 40. Extension of the PALS Act assures that women will have access to annual mammograms beginning at age 40.  

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Posted 6/21/18