Screening mammography is important for reducing race- and ethnicity-associated triple-negative breast cancer (TNBC) disparities among African American and white American patients. At present, there is a 40% higher mortality rate among African American women compared with white American women.
Using data from the Henry Ford Health System, the study investigators identified 243 cases of TNBC that were diagnosed between 2011 and 2015. Of this group, 106 African American patients and 87 white American patients provided enough self-reported data for the authors to evaluate their outcomes. The patients were followed until death, loss to follow-up, or study termination in April 2018. The investigators wrote that “mammography screening-detected cancers were found on routinely scheduled mammography in the absence of clinical symptoms.”
The study authors said that a 2-fold higher incidence of TNBC can partly explain why there is a 40% higher mortality rate among African American women compared with white American women. Although screening mammography improves breast cancer survival through early detection, they said, TNBC is more challenging to detect compared to non-TNBC.
The study authors reported that there were no significant differences among African American and white American patients based on mean (range) age (61.3 [29-90] vs 61.0 [27-90] years, respectively) at diagnosis, mean tumor size (2.2 [0.3-10.0] vs 2.7 [0.1-27.0] cm), or nodal status (node negative: 80 [75.5%] and 68 [78.2%]). The 2 groups of patients had similar frequency for screening-detected disease, and most of their tumors were invasive ductal tumors. The study authors also noted that family histories of breast cancers were similar between the groups.
A majority of the patients—95.8% of African American patients and 88.6% of white American patients—had some form of nonpublic insurance, including Medicare, the study authors said. African American patients also had higher mean body mass index (BMI) scores (32.2 kg/m2 vs 28.6 kg/m2), the investigators found. However, fewer African American patients were referred for genetic testing or counseling compared with white American patients (23 vs 33 patients).
Treatment methods were relatively similar between the 2 groups. Lumpectomies and postoperative or adjuvant chemotherapy were performed in 55.7% (59), 57.5% (61), and 22.6% (24), respectively, of African American patients compared with 59.8% (52), 60.9% (53), and 19.5% (17) of white American patients. The African American patients, however, were less likely to undergo contralateral prophylactic mastectomy, the authors added.
The frequency of local recurrence and distant relapse did not appear statistically significant between the 2 groups, the study authors reported.
Finding TNBC through screening was associated with an improved 4-year overall survival for African American patients (screening-detected cases, 93.2%; 95% CI, 87.0%-99.9%; non—screening-detected cases, 59.1%; 95% CI, 45.8%-76.2%; P <.001), but a similar significant improvement was not seen among white American patients (screening-detected cases, 87.5%; 95% CI, 76.5%-100%; non—screening detected cases, 74.8%; 95% CI, 62.3%-89.7%), the investigators said. For African American patients, the median follow-up time was 50.3 (range, 1-36) months compared with 47.5 (6-91) months for white American patients. No race/ethnicity, age, histology, MIB1 status, BMI, insurance status, or parity were associated with survival, the study authors found.
“Screening mammography successfully detected early stage TNBC, improving outcomes for both African American and white American patients,” the study authors concluded. “Screening mammography is therefore an important strategy for reducing race-/ethnicity-associated breast cancer disparities by optimizing overall survival for both population subsets.”
Chen Y, Susick L, Davis M, et al. Evaluation of triple-negative breast cancer early detection via mammography screening and outcomes in African American and white American patients [published online February 19, 2020]. JAMA Surg. doi: 10.1001/jamasurg.2019.6032.