Polgár Csaba, Fodor János, Major Tibor, Takácsi-Nagy Zoltán, Kásler Miklós, Hammer Josef, Van Limbergen Erik, Németh György
National Institute of Oncology, Department of Radiotherapy, Budapest, Hungary.
Strahlenther Onkol. 2002 Nov;178(11):597-606. doi: 10.1007/s00066-002-0966-z.
The standard technique of radiotherapy (RT) after breast conserving surgery (BCS) is to treat the entire breast up to a total dose of 45-50 Gy with or without tumor bed boost. The majority of local recurrences occur in close proximity to the tumor bed. Thus, the necessity of whole breast radiotherapy has been questioned, and several centers have evaluated the feasibility and efficacy of sole tumor bed irradiation. The aim of this study was to review the current status, controversies, and future prospects of tumor bed irradiation alone after breast conserving surgery.
Published prospective trials evaluating the feasibility and efficacy of radiotherapy confined to the tumor bed following breast conserving surgery were reviewed in order to analyze treatment results.
In three earlier studies, using tumor bed radiotherapy for unselected patients, the incidence of intra-breast relapse was reported in the range of 15.6-37%. However, in nine prospective phase I-II trials, sole brachytherapy (BT) with different dose rates, strict patient selection, and meticulous quality assurance, resulted in 95.6-100% local control rates. To date, only one phase III protocol has been initiated comparing the efficacy of tumor bed brachytherapy alone with conventional whole breast radiotherapy. The ideal extend of the planning target volume (PTV) for tumor bed radiotherapy alone has not been established yet. In most series, PTV was defined as the excision cavity with generous (1-3 cm) safety margins. Minimal requirement for PTV localization is the use of titanium clips to mark the walls of the excision cavity intraoperatively, but the combination of clip demarcation and three-dimensional (3-D) visual information obtained from cross-sectional images seems to be the best method to determine the target volume. 3-D virtual brachytherapy is also a promising method to minimize the chance of geographic miss. Recently developed techniques, such as intraoperative radiotherapy (IORT), as well as accelerated 3-D conformal external beam radiation therapy (3-D-CRT) were also found to be feasible for tumor bed radiotherapy alone.
In spite of the existing arguments against limiting radiotherapy to the tumor bed after breast conserving surgery, results of phase I-II studies suggest that tumor bed radiotherapy alone might be an appropriate treatment option for selected breast cancer patients. Whole breast radiotherapy remains the standard radiation modality used in the treatment of breast cancer, and brachytherapy as the sole modality should be considered as investigational. Further phase-III trials are suggested to determine the equivalence of sole tumor bed radiotherapy, compared with whole breast radiotherapy. Preliminary results with recently developed techniques (CT-image based conformal brachytherapy, 3-D virtual brachytherapy, IORT, 3-D-CRT) are promising. However, more experience is required to define whether these methods might improve outcome for patients treated with tumor bed radiotherapy alone.
保乳手术后放疗（RT）的标准技术是对整个乳房进行治疗，总剂量达45 - 50 Gy，可加或不加瘤床补量。大多数局部复发发生在瘤床附近。因此，全乳放疗的必要性受到质疑，一些中心已评估单纯瘤床照射的可行性和疗效。本研究的目的是综述保乳手术后单纯瘤床照射的现状、争议及未来前景。
回顾已发表的评估保乳手术后局限于瘤床放疗的可行性和疗效的前瞻性试验，以分析治疗结果。
在三项早期研究中，对未选择的患者使用瘤床放疗，乳腺内复发率报告在15.6% - 37%范围内。然而，在九项前瞻性I - II期试验中，采用不同剂量率的单纯近距离放疗（BT）、严格的患者选择和细致的质量保证，局部控制率达到95.6% - 100%。迄今为止，仅启动了一项III期方案，比较单纯瘤床近距离放疗与传统全乳放疗的疗效。单独瘤床放疗的计划靶体积（PTV）的理想范围尚未确定。在大多数系列研究中，PTV被定义为带有足够（1 - 3 cm）安全边缘的切除腔。PTV定位的最低要求是术中使用钛夹标记切除腔壁，但钛夹标记与从横断面图像获得的三维（3 - D）视觉信息相结合似乎是确定靶体积的最佳方法。三维虚拟近距离放疗也是一种有前景的方法，可将遗漏照射范围的几率降至最低。最近开发的技术，如术中放疗（IORT）以及加速三维适形外照射放疗（3 - D - CRT），也被发现单独用于瘤床放疗是可行的。
尽管存在反对保乳手术后将放疗局限于瘤床的观点，但I - II期研究结果表明，单纯瘤床放疗可能是部分乳腺癌患者的合适治疗选择。全乳放疗仍然是乳腺癌治疗中使用的标准放疗方式，而单纯近距离放疗应被视为试验性的。建议进一步开展III期试验，以确定单纯瘤床放疗与全乳放疗的等效性。最近开发的技术（基于CT图像的适形近距离放疗、三维虚拟近距离放疗、IORT、3 - D - CRT）的初步结果很有前景。然而，需要更多经验来确定这些方法是否能改善单纯接受瘤床放疗患者的治疗效果。
