Background: Of women diagnosed with metastatic breast cancer (MBC), 20% to 30% survive ≥5 years. We evaluated data from a large breast cancer program to identify features associated with MBC survival.
Patients and methods: Women diagnosed with MBC in or after 1999 were included. Long-term MBC survival was defined as ≥5 years from date of MBC diagnosis (n = 122), short-term MBC survival as ≤2 years (n = 191). Differences were assessed using t tests, Wilcoxon-Mann-Whitney tests, χ2, and Fisher exact tests. Odds ratios (ORs) were calculated using multivariate logistic regression models.
Results: Long-term survivors were significantly (P < .05) younger, premenopausal, partnered, had estrogen receptor (ER)-positive, progesterone receptor-positive, and HER2-positive disease, lower Charlson Comorbidity Index, lower rates of visceral metastases, and higher household income. After adjustment for potential confounders, de novo MBC, premenopausal status, ER-positive status, and HER2-positive status remained significantly positively associated with long-term survival (respectively: OR, 2.68 [95% confidence interval (CI), 1.48-4.88]; OR, 1.96 [95% CI, 1.02-3.79]; OR, 3.74 [95% CI, 1.72-8.14]; OR, 2.88 [95% CI, 1.61-5.14]). Triple-negative status, visceral with bone metastases, and brain metastases remained negatively associated with long-term survival (respectively: OR, 0.12 [95% CI, 0.05-0.29]; OR, 0.18 [95% CI, 0.07-0.47]; OR, 0.16 [95% CI, 0.04-0.60]). Partner status and household income were significant in univariate but not multivariate analyses.
Conclusion: Diagnosis of de novo MBC, premenopausal status, ER-positive status, and HER2-positive status were positively associated whereas triple-negative status, brain metastases, and visceral with bone metastases were inversely associated with long-term survival. These findings can be applied to better prognosticate survival for MBC patients.
Keywords: Epidemiology; Hormonal therapy; Metastatic breast cancer; Prognostic factors; Survival.
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