Factors Associated with Metastatic Breast Cancer in Patients Who Show Long-Term Stable Disease Status

ABSTRACT

PURPOSE: This study aimed to analyze the basic clinical characteristics and survival of patients with breast cancer whose disease had been stably maintained for more than 24 months after systemic therapy. METHODS: We retrospectively reviewed the medical records of patients with primary breast cancer who underwent surgery. Among these patients, patients with stage IV disease at diagnosis or those who developed distant metastasis during the follow-up period after surgery were included in this analysis. Patients whose disease remained stable for more than 24 months were classified as the long-term stable disease group. The remaining patients were classified as the control group. RESULTS: A total of 245 patients were eligible for this analysis. Patients in the long-term stable disease group showed a lower rate of histologic type III, a higher rate of hormone receptor positivity, and received less adjuvant chemotherapy. In the long-term stable disease group, the most frequent site of metastasis was the lungs, whereas in the control group, it was the bones. Overall survival was significantly better in the long-term stable disease group than in the control group (p<0.001). In univariate analysis, factors affecting the overall survival rate were the duration from diagnosis to metastasis, the absence of lymphatic infiltration, and the presence of hormone receptors. In multivariate analysis, the duration from diagnosis to metastasis and the absence of lymphatic infiltration were significant factors affecting the overall survival rate. CONCLUSION: Disease progression was observed in many patients even after the disease had been stable for more than 24 months after systemic therapy. Although these patients had better outcomes compared with the others, continuous observation and possible additional treatment might be helpful for some patients.