Abstract：
OBJECTIVE: Evidence shows stereotactic ablative body radiotherapy (SABR) is used as a non-invasive ablative therapy in the treatment of multisite oligometastatic (OM) and oligoprogressive (OP) diseases originating from metastatic breast cancer. This study aims to report the treatment outcomes and to investigate what factors that are prognostic in terms of local control, progression-free survival (PFS) and overall survival (OS) in patients receiving SABR for extracranial OM and OP diseases originating from metastatic breast cancer.
METHODS: A retrospective review on treatment records of patients with OM and OP from metastatic breast cancer who underwent SABR at a single was carried out. SABR was performed with daily image-guided radiotherapy (IGRT) using a dedicated robotic SABR machine. Local control, PFS and OS were calculated using Kaplan-Meier statistics and the post-treatment toxicity data was scored following the CTCAE v4.0 protocol. Univariate and multivariate Cox regression tests were used in the subgroup analysis of prognostic factors on PFS and OS including patients\' age, types of follow-up imaging (staging CT only vs whole-body MR/PET), metastases status (OM vs OP), primary breast cancer tumour grade, hormone receptors (ER/PR/HER2) status, change of systemic treatments at SABR, number of metastases, SABR treatment sites and doses.
RESULTS: 56 metastatic breast cancer patients (38 patients with OM and 18 patients with OP) were involved in this retrospective review. The median follow-up was 35.6 months (range 4.0-132.9 months). The estimated local control at 1 , 2 and 5 years were 90.9%, 88.7% and 88.7%, respectively. The estimated median PFS was 19.2 months (95%CI 10.3-28.1 months); the PFS at 1, 2 and 5 years were 63.3%, 44.4% and 33.2%. The estimated OS at 1, 2 and 5 years were 98.0%, 91.9% and 74.3%, respectively with the estimated median OS of 105.1 months (95%CI 51.5-158.7 months). The vast majority of patients tolerated the treatment well with the commonest acute side effects as grade 1 fatigue. There were no statistically significant factors found in OS regression analysis. The types of follow-up imaging, metastases status, oestrogen receptor status, and number of metastases for SABR were statistically significant factors (p < 0.05) in the multivariate Cox regression analysis on PFS.
CONCLUSIONS: There are limited studies published on the efficacy and post-treatment toxicities of metastatic breast cancer OM and OP SABR with adequate length of follow-up. This study confirmed that SABR was a safe, non-invasive treatment option for patients with extracranial OM and OP diseases originated from primary breast cancer in terms of the acceptable post-treatment toxicities.
METHODS: A retrospective review on treatment records of patients with OM and OP from metastatic breast cancer who underwent SABR at a single was carried out. SABR was performed with daily image-guided radiotherapy (IGRT) using a dedicated robotic SABR machine. Local control, PFS and OS were calculated using Kaplan-Meier statistics and the post-treatment toxicity data was scored following the CTCAE v4.0 protocol. Univariate and multivariate Cox regression tests were used in the subgroup analysis of prognostic factors on PFS and OS including patients\' age, types of follow-up imaging (staging CT only vs whole-body MR/PET), metastases status (OM vs OP), primary breast cancer tumour grade, hormone receptors (ER/PR/HER2) status, change of systemic treatments at SABR, number of metastases, SABR treatment sites and doses.
RESULTS: 56 metastatic breast cancer patients (38 patients with OM and 18 patients with OP) were involved in this retrospective review. The median follow-up was 35.6 months (range 4.0-132.9 months). The estimated local control at 1 , 2 and 5 years were 90.9%, 88.7% and 88.7%, respectively. The estimated median PFS was 19.2 months (95%CI 10.3-28.1 months); the PFS at 1, 2 and 5 years were 63.3%, 44.4% and 33.2%. The estimated OS at 1, 2 and 5 years were 98.0%, 91.9% and 74.3%, respectively with the estimated median OS of 105.1 months (95%CI 51.5-158.7 months). The vast majority of patients tolerated the treatment well with the commonest acute side effects as grade 1 fatigue. There were no statistically significant factors found in OS regression analysis. The types of follow-up imaging, metastases status, oestrogen receptor status, and number of metastases for SABR were statistically significant factors (p < 0.05) in the multivariate Cox regression analysis on PFS.
CONCLUSIONS: There are limited studies published on the efficacy and post-treatment toxicities of metastatic breast cancer OM and OP SABR with adequate length of follow-up. This study confirmed that SABR was a safe, non-invasive treatment option for patients with extracranial OM and OP diseases originated from primary breast cancer in terms of the acceptable post-treatment toxicities.
摘要：
目的：证据表明，立体定向消融体放疗（SABR）被用作非侵入性消融疗法，用于治疗源自转移性乳腺癌的多部位寡转移（OM）和寡进展（OP）疾病。这项研究旨在报告治疗结果，并调查哪些因素是局部控制方面的预后因素，接受SABR治疗源自转移性乳腺癌的颅外OM和OP疾病的患者的无进展生存期(PFS)和总生存期(OS).
方法：对转移性乳腺癌OM和OP患者的治疗记录进行回顾性回顾，这些患者在一次接受SABR。使用专用的机器人SABR机在每日图像引导放射治疗（IGRT）的情况下进行SABR。本地控制,使用Kaplan-Meier统计量计算PFS和OS,并按照CTCAEv4.0方案对治疗后毒性数据进行评分。单变量和多变量Cox回归测试用于PFS和OS的预后因素亚组分析，包括患者年龄，随访成像类型（仅分期CT与全身MR/PET），转移状态（OMvsOP），原发性乳腺癌肿瘤分级，激素受体（ER/PR/HER2）状态，SABR全身治疗的变化，转移的数量，SABR治疗部位和剂量。
结果：本回顾性综述涉及56例转移性乳腺癌患者（38例OM患者和18例OP患者）。中位随访时间为35.6个月（范围4.0-132.9个月）。估计本地控制为1，2年和5年为90.9%，88.7%和88.7%，分别。估计的中位PFS为19.2个月（95CI10.3-28.1个月）；1年，2年和5年的PFS为63.3％，44.4%和33.2%。1年，2年和5年的估计OS为98.0％，91.9%和74.3%，分别为105.1个月（95CI51.5-158.7个月）。绝大多数患者对治疗的耐受性良好，最常见的急性副作用为1级疲劳。在OS回归分析中没有发现有统计学意义的因素。后续成像的类型，转移状态，雌激素受体状态，在PFS的多变量Cox回归分析中，SABR的转移数量是有统计学意义的因素（p<0.05）。
结论：发表的关于转移性乳腺癌OM和OPSABR的疗效和治疗后毒性的研究有限，随访时间足够长。这项研究证实SABR是一种安全的，根据可接受的治疗后毒性，对于原发性乳腺癌颅外OM和OP疾病患者的非侵入性治疗选择。
方法：对转移性乳腺癌OM和OP患者的治疗记录进行回顾性回顾，这些患者在一次接受SABR。使用专用的机器人SABR机在每日图像引导放射治疗（IGRT）的情况下进行SABR。本地控制,使用Kaplan-Meier统计量计算PFS和OS,并按照CTCAEv4.0方案对治疗后毒性数据进行评分。单变量和多变量Cox回归测试用于PFS和OS的预后因素亚组分析，包括患者年龄，随访成像类型（仅分期CT与全身MR/PET），转移状态（OMvsOP），原发性乳腺癌肿瘤分级，激素受体（ER/PR/HER2）状态，SABR全身治疗的变化，转移的数量，SABR治疗部位和剂量。
结果：本回顾性综述涉及56例转移性乳腺癌患者（38例OM患者和18例OP患者）。中位随访时间为35.6个月（范围4.0-132.9个月）。估计本地控制为1，2年和5年为90.9%，88.7%和88.7%，分别。估计的中位PFS为19.2个月（95CI10.3-28.1个月）；1年，2年和5年的PFS为63.3％，44.4%和33.2%。1年，2年和5年的估计OS为98.0％，91.9%和74.3%，分别为105.1个月（95CI51.5-158.7个月）。绝大多数患者对治疗的耐受性良好，最常见的急性副作用为1级疲劳。在OS回归分析中没有发现有统计学意义的因素。后续成像的类型，转移状态，雌激素受体状态，在PFS的多变量Cox回归分析中，SABR的转移数量是有统计学意义的因素（p<0.05）。
结论：发表的关于转移性乳腺癌OM和OPSABR的疗效和治疗后毒性的研究有限，随访时间足够长。这项研究证实SABR是一种安全的，根据可接受的治疗后毒性，对于原发性乳腺癌颅外OM和OP疾病患者的非侵入性治疗选择。
