Age disparities in triple-negative breast cancer treatment and outcomes: An NCDB analysis

Race, access to care, and molecular features result in outcome disparities in triple-negative breast cancer (TNBC). We sought to determine the role of age in TNBC disparity by hypothesizing that younger patients receive more comprehensive treatment, resulting in survival differences.

The National Cancer Database was used to identify women with unilateral TNBC treated from 2005 through 2017. Patients were stratified by age (≤40, 41-70, >70); demographics, clinical characteristics, and treatment factors were compared. Logistic regression determined factors associated with treatment received. Survival outcomes were analyzed using a stratified log-rank test.

Of the 168,715 patients, 16,287 (9.6%) were ≤40 years. Patients ≤40 were significantly more likely to present at higher clinical stage (P < .001) and receive neoadjuvant chemotherapy (NAC, P < .001). Bilateral mastectomy was the most common surgery for patients ≤40 (37%), whereas partial mastectomy was most often used in patients 41 to 70 years old (48%) and those >70 (49%) (P < .001). Patients ≤40 years were significantly more likely to undergo both NAC and mastectomy than those >40 (odds ratio 1.5, both P < .05) despite a greater in-breast tumor response in the youngest patients. Patients treated with mastectomy and axillary lymph node dissection had inferior survival outcomes compared to those treated with partial mastectomy and sentinel lymph node biopsy across all 3 age groups (P < .001).

The clinical characteristics of TNBC differ significantly at the extremes of age, likely driving treatment decisions. Although patients ≤40 present with a more advanced disease and appropriately receive NAC, they also undergo more extensive surgery that does not yield a survival benefit. Further research is needed to determine if age disparity is due to oncologic factors or patient and provider preferences.