Top Line: Opinions abound on which cervical nodal levels are at highest risk for nasopharyngeal carcinoma.
The Study: This large retrospective study categorized all involved cervical lymph node levels for 960 patients with node-positive nasopharyngeal carcinoma. The levels most frequently involved were: VIIa (RP nodes) 86%, IIb 84%, IIa 62%, III 47%, Va 25%, and IVa 15%. Levels with a 5-10% frequency of involvement were Vb 6.0%, Ib 5.4%, and posterior to level V 5.5%—this last one, the deepest most region between the trapezius muscle and the scapular levator, is particularly interesting as it is not typically described as a distinct area to cover. Positive nodes at the less frequent levels typically correlated with positive nodes at higher-frequency adjacent levels. For example, the area posterior to level V was typically involved only if level V was, as well. Nodal levels with < 5% frequency of involvement were: IVb 3.1%, Vc 1.8%, VIII 1.0%, VIIb 0.7%, and 0% for Ia, VIa, IX, and X. A common pattern was that nodal levels with less frequent involvement typically correlated with involvement of numerous other levels. In other words, they were only involved when there was extensive nodal spread to multiple levels.
TBL: This study suggests the intermediate dose radiation volume for nasopharyngeal cancer should usually include levels II-IVa/Va with the addition of Ib/IVb/Vb/posterior to V when adjacent levels are involved. | Jiang, Radiother Oncol 2021