A comprehensive evaluation of de novo metastatic breast cancer trends by subtype from the Dallas Metastatic Cancer Study.

Background: The Dallas Metastatic Cancer Study is a clinical database established to examine local trends associated with the diagnosis and treatment of de novo metastatic breast cancer and identify factors for further evaluation. Clinical characteristics of patients with de novo metastatic breast cancer are often underreported in the literature.

Methods: We report data from 2010 to 2021 for patients with de novo metastatic breast cancer along with the impact of clinical variables such as age, BMI, race and ethnicity, insurance status, hypertension, diabetes, and site of metastasis with survival analysis with respect to subtype.

Results: Black race (HR 2.07, 95% CI 1.56-2.74), public insurance (HR 1.64, 95% CI 1.23-2.18), no insurance (HR 1.69, 95% CI 1.24-2.31), hypertension (HR 1.50, 95% CI 1.18-1.91), diabetes (HR 1.69, 95% CI 1.24-2.31), and visceral metastases including brain (HR 1.68, 95% CI 1.20-2.36), liver (HR 1.80, 95% CI 1.40-2.30), and lung (HR 1.50, 95% CI 1.17-1.92) were associated with increased mortality and remained significant when controlled for subtype. In the multivariate analysis, diabetes (HR 1.74, 95% CI 1.22-2.49) and presence of liver metastases (HR 1.97, 95% CI 1.43-2.49) remained independently associated with decreased overall survival regardless of subtype and other variables. Patients diagnosed at 40 and younger were less likely to have hypertension and diabetes, more likely to be Hispanic, and showed distinct subtype distributions compared to those diagnosed at older ages.

Conclusions: Future work will focus on these associations at the patient level to identify targets for intervention.