The US Preventative Service Task Force (USPSTF), a group of independent experts specializing in disease prevention and evidence-based medicine, provides recommendations on strategies to improve the health of the American public through preventative services. In 2009, the USPSTF recommendations for women at an average risk of breast cancer changed, leading to decreased mammography rates nationwide.
Prior to the 2009 recommendations, USPSTF’s 2002 guidance included mammograms for all women aged 40 or older every one to two years. However, some experts raised concerns about psychological distress resulting from false-positive results and other complications accompanying overdiagnosis.
The controversial 2009 guidance reduced the recommended mammography scheduling to include a degree of individualized decision-making. Under the 2009 guidelines, the USPSTF recommended screening every other year for women aged 40 to 49 and routine biennial screening for women aged 50 to 74. The subsequent reductions in breast cancer screening caused some experts to worry that late-stage breast cancer diagnoses and associated poorer outcomes resulting from more difficult-to-treat cases would arise.
To thoroughly investigate the potential long-term implications of the 2009 change in guidance for breast cancer screening, a dedicated team of researchers meticulously evaluated the incidence of breast cancer at each stage of diagnosis. Their comprehensive study, the findings of which were recently published in JAMA Network Open provides a new understanding the impact of the 2009 USPSTF guidelines.
The population-based, epidemiological study included over two million women 40 years or older. The researchers obtained data from the Surveillance, Epidemiology, and End Results (SEER) Program database operated by the National Cancer Institute (NCI). The researchers considered the age and stage associated with national incidence rates. In addition, the study delved into the impact guideline changes had on the number of invasive surgical procedures (mastectomies) performed. The study grouped women based on age at diagnosis into three categories: 40-49 years (2,022,250 women), 50 – 74 years (1,279,542 women), and 75 years and older (388,445 women).
The study revealed that rates of breast cancer in situ, a non-invasive disease that has not moved from the location of origin, declined about 30% in the 50 – 74 year group since 2009. Localized breast cancer, where cells remain in a specific area of the breast but have not traveled to the lymph node or other tissues, increased in both groups including women under 74 years. The study detected no change in rates of regional breast cancer, cases that have spread to the lymph nodes of nearby tissues such as the chest wall. Finally, cases of distant breast cancer, in which cancer cells have metastasized to distant parts of the body, such as the brain or bone, remained stable in women in the 40 – 49 years and 50 – 74 years groups. However, the rates of distant breast cancer cases increased by about 40% in women 75 years and older.
The findings were encouraging when investigating rates of invasive surgical procedures (treatments that could result in more complications or adverse effects). Between 2013 and 2019, the proportion of cases treated with total mastectomy decreased in the women with localized cancer in each of the two younger age groups. In the same timeframe, partial mastectomy cases increased in women in the 50 – 74 year group.
The authors conclude that the changes in USPSTF guidance in 2009 have led to positive outcomes. The decrease in in situ breast cancer cases, which was expected to coincide with the reduced use of mammograms, did not lead to more cases of advanced cancer or fewer partial mastectomies. This suggests that the 2009 guidelines have not resulted in adverse outcomes, providing a sense of optimism about the changes in breast cancer screening recommendations.
Sources: Ann Intern Med (2009), Ann Intern Med (2002), JAMA Network Open
