Wheatley D, Adwani A, Ebbs S, Hanson J, Ross G, Sharma A K, Wells P, Yarnold J
Department of Radiotherapy, The Royal Marsden Hospital, Sutton, Surrey, UK.
Clin Oncol (R Coll Radiol). 2005 Feb;17(1):32-8. doi: 10.1016/j.clon.2004.09.011.
To determine (1) if the lower border of a standard anterior radiotherapy field to the supraclavicular fossa matches the upper limit of level II/III axillary dissection; and (2) whether standard lung blocks in patients prescribed axillary radiotherapy shield target axillary tissue in women with breast cancer.
Between 1999 and 2001, 30 women with breast cancer undergoing level II/III axillary dissection had titanium clips placed to define the upper and medial limits of surgery. At radiotherapy planning, a supraclavicular fossa field similar to that described in the UK START trial protocol was simulated, with head twist applied to position the inferior field border (50% isodose) 1 cm below and parallel to the lower border of the clavicle. The field position was recorded on X-ray film. The location of the most superior axillary clip was measured in relation to this inferior field border on the X-ray film. The location of the most medial clip was measured in relation to the lung/chest wall interface.
The median distance between the most superior clip and the inferior border of the supraclavicular field was 3.6 cm (0.8-6.9 cm), representing significant underlap in all cases. In addition, five out of 30 (17%) patients had surgical clips over 2.0 cm medial to the lung/chest wall interface, suggesting that medial lymph nodes in an undissected axilla would be shielded by standard lung blocks in patients prescribed axillary radiotherapy.
Current standard radiation fields to the supraclavicular fossa, as applied in this study, leave apical axillary lymph nodes untreated in a high proportion of patients. Standard lung shielding, as applied in this study to patients simulated for axillary radiotherapy, protect medial axillary lymph nodes in a few patients. A change in practice is recommended.
确定（1）标准前位放疗野至锁骨上窝的下缘是否与Ⅱ/Ⅲ级腋窝淋巴结清扫的上限相匹配；以及（2）接受腋窝放疗的患者使用的标准肺部挡铅是否能遮挡乳腺癌女性患者的目标腋窝组织。
1999年至2001年期间，30例接受Ⅱ/Ⅲ级腋窝淋巴结清扫的乳腺癌女性患者放置了钛夹以确定手术的上界和内侧界。在放疗计划时，模拟了一个类似于英国START试验方案中描述的锁骨上窝野，通过头部旋转将下野边界（50%等剂量线）置于锁骨下缘下方1 cm并与之平行。野的位置记录在X线片上。在X线片上测量最上方腋窝钛夹相对于这下野边界的位置。测量最内侧钛夹相对于肺/胸壁界面的位置。
最上方钛夹与锁骨上野下缘之间的中位距离为3.6 cm（0.8 - 6.9 cm），表明在所有病例中均存在明显的覆盖不足。此外，30例患者中有5例（17%）的手术钛夹位于肺/胸壁界面内侧超过2.0 cm处，这表明在接受腋窝放疗的患者中，标准肺部挡铅可遮挡未清扫腋窝中的内侧淋巴结。
本研究中应用的当前锁骨上窝标准放疗野，在很大比例的患者中使腋窝顶端淋巴结未得到治疗。本研究中应用于模拟腋窝放疗患者的标准肺部遮挡，在少数患者中可保护腋窝内侧淋巴结。建议改变治疗方式。
