[Background] Patients with advanced breast cancer face the challenge of controlling a variety of symptoms as treatment progresses. Some of these symptoms cannot be explained solely by damage to metastatic organs.
[Purpose] To identify the pathological factors underlying symptoms seen in patients with advanced breast cancer, stratify cases, and examine their clinical significance.
Methods: A retrospective observational study was conducted on cases who were diagnosed with advanced breast cancer and died at Cancer Institute Ariake Hospital between 2005 and 2018. Factor analysis and hierarchical cluster analysis were performed, and the prognosis of each cluster was compared using the Kaplan-Meier method.
Results: Seven factors were extracted from 466 cases and classified into eight clusters. C3 (n=98) and C5 (n=79) had a diverse combination of metastatic organs. C8 (n=19) was characterized by liver or bone metastasis, with 42% only having bone metastasis. C8 tended to have the poorest prognosis (p=0.068). C8 had a high proportion of hormone receptor-positive breast cancer (69%), while C5 had a high proportion of triple-negative breast cancer (41%).
[Conclusion] Cases were stratified based on symptoms and pathology, and differences in prognosis and pathological characteristics were shown for each cluster. Since certain clusters have characteristic pathological conditions that cannot be explained solely by damage to metastatic organs, detailed investigation is required.
