Yashar Catheryn M, Blair Sarah, Wallace Anne, Scanderbeg Dan
Department of Radiation Oncology, University of California San Diego, La Jolla, 92093-0843, USA.
Brachytherapy. 2009 Oct-Dec;8(4):367-72. doi: 10.1016/j.brachy.2009.03.190. Epub 2009 Sep 9.
Accelerated partial breast irradiation is becoming increasingly popular. The Cianna single-entry high-dose-rate applicator, Strut-Adjusted Volume Implant (SAVI, Cianna Medical, Aliso Viejo, CA), contains peripheral struts allowing greater planning flexibility for small-breasted women, technically easier insertion, and normal tissue exposure minimization. This study evaluates early clinical experience.
Thirty patients treated with the SAVI with a median followup of 12 months were evaluated. The median age was 59.5. Tumor size averaged 0.9cm. Fifteen cancers were ductal carcinoma in situ (50%), 1 was invasive lobular (3.3%), 4 were tubular (6.7%), and the rest infiltrating ductal (40%). Most of them were estrogen receptor (ER) positive (90%). Nine women (30%) were premenopausal.
Dosimetry was outstanding with median V90, V150, and V200 of 96.2%, 24.8, and 12.8cc. There were no symptomatic seromas, and one report of asymptomatic fat necrosis seen on mammogram at 1 year. In patients who had skin spacing of less than 1cm, the median skin dose was 245cGy/fraction. The median rib and lung dose per fraction for those patients with either structure less than 1cm was 340 and 255cGy (75% of prescribed dose), respectively. There have been no local recurrences to date.
Early clinical experience with the SAVI demonstrates the ease of placement of a single-entry brachytherapy device combined with the increased dose modulation of interstitial brachytherapy. Dose to normal structures has remained exceedingly low. Almost half of evaluated patients were not candidates for other single-entry brachytherapy devices because of skin spacing or breast size, demonstrating an expansion of candidates for single-entry partial breast brachytherapy.
加速部分乳腺照射正变得越来越流行。Cianna单入路高剂量率施源器，即支柱调整体积植入物（SAVI，Cianna Medical公司，加利福尼亚州阿利索维耶荷），其周边支柱可为小乳房女性提供更大的计划灵活性、技术上更容易插入且能将正常组织暴露降至最低。本研究评估早期临床经验。
对30例接受SAVI治疗且中位随访时间为12个月的患者进行评估。中位年龄为59.5岁。肿瘤大小平均为0.9cm。15例癌症为原位导管癌（50%），1例为浸润性小叶癌（3.3%），4例为管状癌（6.7%），其余为浸润性导管癌（40%）。其中大多数为雌激素受体（ER）阳性（90%）。9名女性（30%）为绝经前。
剂量测定结果出色，V90、V150和V200的中位数分别为96.2%、24.8和12.8cc。没有出现有症状的血清肿，1例报告在1年时乳房X线照片上发现无症状脂肪坏死。皮肤间距小于1cm的患者，皮肤剂量中位数为245cGy/分次。对于结构小于1cm的患者，每次分割时肋骨和肺的剂量中位数分别为340和255cGy（规定剂量的75%）。迄今为止没有局部复发。
SAVI的早期临床经验表明，单入路近距离放射治疗装置易于放置，同时结合了组织间近距离放射治疗增加的剂量调节。对正常结构的剂量一直极低。由于皮肤间距或乳房大小，近一半接受评估的患者不适合使用其他单入路近距离放射治疗装置，这表明单入路部分乳腺近距离放射治疗的适用人群有所扩大。
