Malignant Phyllodes Tumors of the Breast: Association Between Race, Clinical Features, and Outcomes

We sought to investigate associations between race, clinical characteristics, and outcomes among patients with malignant phyllodes of the breast.

Malignant phyllodes cases were identified using Surveillance Epidemiology and End Results database. We used chi-square tests to compare characteristics between racial groups and multinomial logistic regression to calculate relative risk ratios (RRR) and 95% confidence intervals (CI) comparing the likelihood of having particular characteristics by race. Survival analyses included Cox regression and Kaplan-Meier functions.

Among 1202 patients included, mean age was 51.7 y and 55.2% were white. Compared to whites, blacks were younger (mean age 45.7 versus 55.1 y; P < 0.001), and more likely to have tumors 51-100 mm (RRR = 1.91; 95% CI: 1.20-3.05) and tumors > 100 mm (RRR = 2.52; 95% CI: 1.56-4.05) than tumors ≤ 50 mm in size. Compared to whites, Hispanics were younger (mean age 46.7 versus 55.1 y; P < 0.001), and more likely to have tumors 51-100 mm (RRR = 1.46; 95% CI: 1.01-2.11) than tumors ≤ 50 mm in size. Asians were more likely to have tumors 51-100 mm (RRR = 1.52; 95% CI: 1.01-2.30) and tumors > 100 mm (RRR = 1.61; 95% CI: 1.03-2.52) than tumors ≤ 50 mm in size, and more likely to have tumors that extended beyond the breast tissue (RRR = 1.87; 95% CI: 1.05-3.31), compared to whites. Survival was similar for blacks (HR = 1.48; 95% CI: 0.80-2.76), Hispanics (HR = 1.02; 95% CI: 0.54-1.93), and Asians (HR = 1.13; 95% CI: 0.63-2.01) compared to whites.

Further research into factors contributing to extensive disease at presentation among minorities is warranted.