Department of Radiation Medicine, NorthShore University HealthSystem, 2650 Ridge Ave, Evanston, IL 60201, USA.
Radiat Oncol. 2012 Feb 6;7:17. doi: 10.1186/1748-717X-7-17.
There are limited data on accelerated partial breast irradiation (APBI) using external beam techniques. Moreover, there are recent reports of increased fibrosis and unacceptable cosmesis with APBI using external beam with BID fractionation. We adopted a once daily regimen of APBI with fractionation similar to that shown to be effective in a Canadian randomized trial of whole breast irradiation. It is unclear whether patients with DCIS or invasive lobular carcinoma (ILC) are suitable for APBI.
The retrospective cohort included 310 patients with 312 tumors of T1-T2N0-N1micM0 invasive ductal carcinoma (IDC), ILC, or Tis (DCIS) treated with APBI via external beam. Most patients were treated using IMRT with 16 daily fractions of 270 cGy to a dose of 4320 cGy. The target volume included the lumpectomy cavity plus 1.0 cm to account for microscopic disease and an additional 0.5 to 1.0 cm for setup uncertainty and breathing motion. Ipsilateral breast failure (IBF) was pathologically confirmed as a local failure (LF) or an elsewhere failure (EF).
Median follow-up was 49 months. Among the 312 cases, 213 were IDC, 31 ILC, and 68 DCIS. Median tumor size was 1.0 cm. There were 9 IBFs (2.9%) including 5 LFs and 4 EFs. The IBF rates among patients with IDC, ILC, and DCIS were 2.4%, 3.2%, and 4.4%, respectively, with no significant difference between histologies. When patients were analyzed by the ASTRO APBI consensus statement risk groups, 32% of treated cases were considered suitable, 50% cautionary, and 18% unsuitable. The IBF rates among suitable, cautionary, and unsuitable patients were 4.0%, 2.6%, and 1.8%, respectively, with no significant difference between risk groups. Acute skin reactions were rare and long-term cosmetic outcome was very good to excellent.
External beam APBI with once daily fractionation has a low rate of IBF consistent with other published APBI studies. The ASTRO risk stratification did not differentiate a subset of patients with a higher rate of IBF. APBI may be an appropriate treatment for women with DCIS and ILC.
目前关于采用外照射技术的加速部分乳房照射（APBI）的数据有限。此外，最近有报道称，采用每日一次分割的 APBI 与每日两次分割相比，会增加纤维化和不可接受的美容效果。我们采用了与加拿大全乳照射随机试验中显示有效的分割方式相似的单次分割的 APBI 方案。目前尚不清楚 DCIS 或浸润性小叶癌（ILC）患者是否适合 APBI。
该回顾性队列包括 310 例 T1-T2N0-N1micM0 浸润性导管癌（IDC）、ILC 或Tis（DCIS）患者，共 312 个肿瘤，均采用外照射进行 APBI 治疗。大多数患者采用调强放疗（IMRT），16 次分割，每次 270cGy，总剂量为 4320cGy。靶区包括保乳手术腔加 1.0cm 以覆盖显微镜下疾病，外加 0.5-1.0cm 以考虑摆位不确定性和呼吸运动。同侧乳房失败（IBF）被病理证实为局部失败（LF）或远处失败（EF）。
中位随访时间为 49 个月。在 312 例病例中，213 例为 IDC，31 例为 ILC，68 例为 DCIS。中位肿瘤大小为 1.0cm。发生 9 例 IBF（2.9%），其中 5 例为 LF，4 例为 EF。IDC、ILC 和 DCIS 患者的 IBF 发生率分别为 2.4%、3.2%和 4.4%，组织学之间无显著差异。根据 ASTRO APBI 共识声明风险组对患者进行分析，32%的治疗病例被认为是合适的，50%是谨慎的，18%是不合适的。合适、谨慎和不合适患者的 IBF 发生率分别为 4.0%、2.6%和 1.8%，风险组之间无显著差异。急性皮肤反应罕见，长期美容效果良好至极好。
每日一次分割的外照射 APBI 的 IBF 发生率与其他已发表的 APBI 研究一致，较低。ASTRO 风险分层并不能区分 IBF 发生率较高的亚组患者。APBI 可能是 DCIS 和 ILC 患者的一种合适的治疗选择。
