Match lines drawn.
Top Line: Do regional nodal target volumes potentially miss at-risk nodal regions in the supraclavicular fossa?
The Study: The medial inferior supraclavicular region is an important but often overlooked part of the nodal target volume for locally advanced breast cancer. This expert editorial points out the importance of this anatomic site and potential pitfalls in adequately covering it during regional nodal irradiation. The medial inferior supraclavicular nodes typically lie just behind the clavicular head near the junction of the jugular and subclavian veins. Two thirds of patients with supraclavicular nodal metastases have disease at the junction of the jugular and subclavian veins. However, this site often falls near the match line and could even be outside the field if the match line is raised above the inferior border of the clavicular head. Furthermore, when following some contouring atlases, target volumes for breast regional lymph nodes may actually skip this region between the inferior supraclavicular volume and the superior border of the breast/chest wall or the internal mammary volume. Such a gap could be particularly problematic as we increasingly rely on volume-based treatment techniques such as IMRT. The experts point out that despite the descriptions and appearance of nodal volumes in contouring atlases, the volume between the top of the breast/chest wall or IMN and the inferior supraclavicular nodes should be contiguous. Their final recommendations are 1) the supraclavicular field should include the clavicular head as a landmark for the medial inferior supraclavicular fossa, and 2) the match line should typically be at the bottom of the clavicular head. When the match line is placed higher, care should be taken to ensure the tangent field is deep enough to cover this space.
TBL: Contouring the contiguous space between the inferior supraclavicular fossa and the upper chest and IMN ensures adequate coverage of important regional lymph nodes. | Marks, Pract Radiat Oncol 2022