Abstract:
Objective To investigate the clinicopathological characteristics and prognostic factors in breast carcinoma patients with bone-only metastasis (BOM).
Methods A total of 967 patients with metastatic breast cancer treated in Tianjin Medical University Institute and Hospital between January 2009 and December 2016 were screened, and the case data were retrospectively analyzed. These data involve 180 cases in the BOM group and 787 cases in the non-BOM group. We performed univariate analysis and Cox regression model multivariate analysis of prognostic factors in patients with BOM. Subgroup analysis was performed according to the hormone receptor (HR) status, number of bone metastases, and treatment approaches.
Results Patients in the BOM group had a median progression-free survival (PFS) of 19.4 months, and non-BOM patients had a median PFS of 10.0 months. Patients in the BOM group had a median overall survival (OS) of 45.6 months. The proportions of patients with HR positivity were 81.7% (147/180) in the BOM group and 64.7% (509/787) in the non-BOM group (P < 0.001). Cox regression model multivariate analyses found that HR status, location of bone metastases, number of bone metastases, and treatment approach were independent factors influencing the prognosis of patients with BOM. Among patients with HR-positive BOM, the prognosis of patients receiving endocrine therapy (P=0.004) or combinatory therapy (P < 0.001) was significantly better than that of patients receiving chemotherapy alone. The number of bone metastases and endocrine therapy were independent prognostic factors in patients with HR-positive BOM. Patients with single bone metastases who received endocrine therapy (P=0.004) or combinatory therapy (P=0.002) had better prognosis than patients who received chemotherapy alone. Patients with multiple bone metastases who received combinatory therapy had better prognosis than patients who received endocrine therapy (P=0.04) or chemotherapy alone (P < 0.001).
Conclusions For HR-positive BOM patients, especially those with single metastases, endocrine therapy can obtain satisfactory outcomes. For patients with multiple metastases, combinatory therapy can be considered.