Ryutaro Mori - Department of Surgical Oncology, Gifu University Graduate School of Medicine, ۱-۱ Yanagido,۵۰۱-۱۱۹۴, Gifu, Japan
Manabu Futamura - Department of Surgical Oncology, Gifu University Graduate School of Medicine, ۱-۱ Yanagido,۵۰۱-۱۱۹۴, Gifu, Japan
Yoshimi Asano - Department of Surgical Oncology, Gifu University Graduate School of Medicine, ۱-۱ Yanagido,۵۰۱-۱۱۹۴, Gifu, Japan
Akira Nakakami - Department of Surgical Oncology, Gifu University Graduate School of Medicine, ۱-۱ Yanagido,۵۰۱-۱۱۹۴, Gifu, Japan
Kazuhiro Yoshida - Department of Surgical Oncology, Gifu University Graduate School of Medicine, ۱-۱ Yanagido, ۵۰۱-۱۱۹۴, Gifu, Japan

Background: Bone-only metastatic breast cancer is believed to be non-lifethreatening,and mild therapy is frequently selected to avoid adverse events of drugtherapy. However, the prognoses of such patients are not well studied.Methods: Patients who received drug therapies for metastatic breast cancerbetween ۲۰۰۴ and ۲۰۱۶ at our institution were divided into the “Bone-onlymetastasis”, “non-visceral”, and “visceral” groups based on the mode of the firstmetastasis, and the efficacy of the first-line therapy and survival of these patientswere compared.Results: There were ۱۳۱ eligible patients, and the bone-only metastasis, nonvisceral,and visceral groups included ۲۶, ۲۵, and ۸۰ patients, respectively. Themedian survival time (MST) of the overall survival (OS) in each group was ۳۵.۱,۳۴.۹, and ۳۷.۴ months, respectively (p=۰.۷۱). The clinical benefit rates of first-linetherapy in the bone-only metastasis, non-visceral, and visceral groups were ۶۶.۷%,۴۵%, and ۶۹.۳%, respectively, and the MST of the time to treatment failure (TTF)in each group was ۶.۳, ۵.۵, and ۵.۸ months, respectively, showing that the efficacyof first-line therapy did not significantly differ among the groups. In the bone-onlymetastasis group, patients with <۵ metastases tended to have a good prognosis, andthose with a low nuclear grade and long first-line therapy duration had asignificantly better prognosis than others.Conclusion: The patients with bone-only metastasis had a similar prognosisand treatment response to those with other modes of metastasis, and the patientswith a good response to the first-line therapy had a good prognosis.

Secondary breast neoplasms, bone metastasis, prognosis