A nationwide multicenter cohort study on particle therapy was launched by the Japanese Society for Radiation Oncology in Japan in May 2016. We analyzed the outcome of proton beam therapy (PBT) for liver oligometastasis in breast cancers. Cases in which PBT was performed at all Japanese proton therapy facilities between May 2016 and February 2019 were enrolled. The patients were selected based on the following criteria: the primary cancer was controlled, liver recurrence without extrahepatic tumors and no more than three liver lesions. Fourteen females, with a median age of 57 years (range, 44–73) and 22 lesions, were included. The median lesion size, fraction (fr) size and biological effective dose were 44 (20–130) mm, 6.6 (2–8) gray (Gy) (relative biological effectiveness)/fr and 109.6 (52.7–115.2) Gy, respectively. The median follow-up period was 22.8 (4–54) months. The 1-, 2- and 3-year local control (LC) rates of liver metastasis from breast cancer were 100% for all. The 1-, 2- and 3-year overall survival rates were 85.7, 62.5 and 62.5%, respectively. The 1-, 2- and 3-year progression-free survival (PFS) rates were 50.0%, 33.3%, and 16.7%, respectively. The median PFS time was 16 months. Only one patient did not complete PBT due to current disease progression. One patient had Grade 3 radiation-induced dermatitis. None of the patients experienced radiation-induced liver failure during the acute or late phase. Owing to the low incidence of adverse events and the high LC rate, PBT appears to be a feasible option for liver oligometastasis in breast cancers.

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日本全国质子束治疗乳腺癌肝寡转移队列数据

日本放射肿瘤学会于 2016 年 5 月在日本启动了一项关于粒子治疗的全国性多中心队列研究。我们分析了质子束治疗 (PBT) 治疗乳腺癌肝脏寡转移的结果。纳入2016年5月至2019年2月期间在日本所有质子治疗机构进行过PBT的病例。选择患者的标准为：原发肿瘤得到控制、肝脏复发且无肝外肿瘤、肝脏病灶不超过三个。包括 14 名女性，中位年龄 57 岁（范围，44-73 岁），有 22 个病变。中位病灶大小、分数 (fr) 大小和生物有效剂量分别为 44 (20–130) mm、6.6 (2–8) 戈瑞 (Gy)（相对生物有效性）/fr 和 109.6 (52.7–115.2) Gy 。中位随访期为 22.8（4-54）个月。乳腺癌肝转移的1年、2年和3年局部控制（LC）率均为100%。 1年、2年和3年总生存率分别为85.7%、62.5%和62.5%。 1年、2年和3年无进展生存率(PFS)分别为50.0%、33.3%和16.7%。中位 PFS 时间为 16 个月。只有一名患者由于当前疾病进展而未完成 PBT。一名患者患有 3 级放射性皮炎。没有患者在急性期或晚期出现放射诱发的肝衰竭。由于不良事件发生率低且LC率高，PBT似乎是乳腺癌肝寡转移的可行选择。