Mammography could ‘mitigate mortality disparities’ in triple-negative breast cancer
Screening mammography detected early-stage triple-negative breast cancer and led to improved survival outcomes among black women and white women, according to a research letter published in JAMA Surgery.
“The increased burden of triple-negative breast cancer among black women definitely contributes to breast cancer outcome disparities and the higher breast cancer mortality rates that are seen among black women compared with white women,” Lisa A. Newman, MD, MPH, FACS, FASCO, chief of the division of breast surgery and director of the Interdisciplinary Breast Program at Weill Cornell Medicine, told Healio.
“It is therefore imperative that we identify strategies that improve triple-negative breast cancer outcomes in order to mitigate mortality disparities," she added. "Our study of triple-negative breast cancer survival in the diverse metropolitan Detroit population allowed us to address this challenge.”
Compared with white women, black women have a 40% higher breast cancer mortality rate and twofold higher incidence of biologically aggressive triple-negative disease. Although mammography is known to improve detection and survival rates, triple-negative disease is more difficult to detect, and the effectiveness of screening mammography in reducing disparities among this patient population is unknown.
Newman and colleagues analyzed data of women in the Henry Ford Health System database who self-reported as black (n = 106) or white (n = 87) and had been diagnosed with nonmetastatic triple-negative breast cancer between January 2011 and December 2015. They followed all women until death, loss to follow-up or study termination — whichever occurred first.
Researchers observed no significant differences between black women and white women in mean age at diagnosis (61.3 years vs. 61 years) or mean tumor size (2.2 cm vs. 2.7 cm).
The majority of black women (75.5%) and white women (78.2%) had node-negative disease. Moreover, 84% of black women and 77% of white women had invasive ductal tumors.
Similar proportions of black and white women had screening-detected disease (58.5% vs. 44.8%), E3 ubiquitin-protein ligase MIB1/KI-67 scores of 30% or higher (52.8% vs. 48.3%), lymphovascular invasion (10.4% vs. 17.2%) and high-grade pathology (79.2% vs. 72.4%).
More than half (55.7%) of black women underwent lumpectomy, compared with 59.8% of white women. In addition, 57.5% of black women received postoperative or adjuvant chemotherapy and 22.6% received neoadjuvant chemotherapy, whereas 60.9% of white women received postoperative adjuvant chemotherapy and 19.5% received neoadjuvant chemotherapy. Black women appeared less likely to undergo contralateral prophylactic mastectomy (1.9% vs. 11.5%; P = .01).
Median follow-up was 50.3 months for black women and 47.5 months for white women.
Among black women, detection of triple-negative disease via screening mammography was associated with significant improvement in 4-year OS compared with cases not detected through screening (93.2% vs. 59.1%; P < .001). Researchers also observed a higher rate of 4-year OS among white women with screening-detected vs. nonscreening-detected disease (87.5% vs. 74.8%), although the difference was not significant.
Overall factors associated with longer survival included screening-detected disease (HR = 0.3; 95% CI, 0.1-0.5), non-T1 disease (HR = 3.5; 95% CI, 1.8-6.9) and node-positive disease (HR = 3.4; 95% CI, 1.8-6.7).
Factors associated with shorter OS included high-grade disease (HR = 2.7; 95% CI, 0.96-7.7), lymphovascular invasion (HR = 3.2; 95% CI, 1.5-7.2) and receiving adjuvant or neoadjuvant chemotherapy (HR = 0.4; 95% CI, 0.2-0.8).
“We found that screening mammography was an effective strategy for early detection of triple-negative breast cancer, and we also demonstrated that triple-negative breast cancer detection via screening mammography was associated with improved survival for both [black women and white women],” Newman told Healio.
“These findings are clinically relevant because the value of screening mammography has been questioned by some health outcomes researchers, and also because triple-negative breast cancer has typically been perceived as being more difficult to detect on routine mammographic imaging,” she added. “We look forward to replicating this work in larger populations of women, and with longer follow-up.” – by Jennifer Southall
For more information:
Lisa A. Newman, MD, MPH, FACS, FASCO, can be reached at Weill Cornell Medicine, 525 E. 68th St., New York, NY 10065; email: firstname.lastname@example.org.
Disclosures: Newman reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.