LAUSR

Abstract Background/Aim: Despite advances in the treatment of breast cancer, metastatic breast cancer (MBC) remains difficult to cure, and few MBC patients survive 10 years after receiving a breast cancer metastasis diagnosis. We collected the cases of patients with MBC who survived >10 years post-metastasis diagnosis and assessed the patients’ characteristics. Patients and Methods: We retrospectively analyzed the cases of 245 consecutive patients diagnosed with MBC between January 2005 and December 2012 at our institution. Among them, 167 patients with confirmed survival of >10 years (i.e., long-term survival) or confirmed death at ≤10 years post-metastasis diagnosis were enrolled. Results: There were 22 patients with MBC who survived >10 years. Regarding the cancer subtypes, 11 patients (50%) with long-term survival were HER2-positive. Seven of the 11 patients with HER2-positive MBC have been without recurrence although anti-HER2 therapy was discontinued. Triple-negative breast cancer (TNBC) was most common in the patients who survived ≤5 years but was not present in the >10-year survival group. In the HER2-negative cases, more cases in the long-term survival group were treated with local therapy (34.4% in the <5-year survival group, 43.8% in the 5-10-year group, and 72.7% in the >10-year group). Conclusion: MBC patients who survive >10 years after being diagnosed with metastasis are more likely to be HER2-positive and treated with local therapy. This suggests the efficacy of anti-HER2 therapy, and, conversely, clarifies unmet needs in TNBC and luminal-type MBC. The usefulness of local therapy was also supported by our findings.