Neck Node Levels and Their Anatomical Boundaries in Head and Neck Cancer

Clinical Significance and Management

The National Comprehensive Cancer Network recommends that the type of neck dissection (comprehensive or selective) is determined based on the clinical staging and primary tumor location 1, 2
For N0 disease, selective neck dissection typically includes at least levels I-III for oral cavity tumors 1, 2
For N0 disease, selective neck dissection typically includes at least levels II-IV for oropharynx tumors 1, 2
For N1-N2 disease, selective or comprehensive neck dissection may be performed 1, 2
For N3 disease, comprehensive neck dissection is recommended 1, 2

On imaging, suspicious features of lymph nodes include rounded shape, loss of fatty hilum, heterogeneous internal architecture, necrotic centers, extracapsular extension, and irregular borders 3
Nodes greater than 1.5 cm in size are considered suspicious 3
Most masses greater than 3 cm in diameter typically represent confluent nodes or tumor in soft tissues rather than single lymph nodes 4

Histologic examination of a selective neck dissection specimen typically includes 6 or more lymph nodes 4
Radical or modified radical neck dissection specimens usually include 10 or more lymph nodes 4

The National Comprehensive Cancer Network (NCCN) guidelines establish a two-tiered classification system for neck dissections, which includes comprehensive and selective neck dissections 5, 6
A comprehensive neck dissection removes all lymph node groups included in a classic radical neck dissection (levels I-V), and is recommended for N3 disease 5, 6
A selective neck dissection encompasses three or fewer nodal levels based on predictable patterns of lymphatic spread, and is recommended for N0 disease 5, 6
For laryngeal and hypopharyngeal primaries, a dissection of levels II-VI may be considered a comprehensive neck dissection variant, as level I is rarely at risk from these primary sites, and level VI inclusion is specifically appropriate for infraglottic laryngeal cancers 5, 6

A neck dissection involving levels II-VI should be described as an "extended selective neck dissection" specifying levels II-VI, as it exceeds the three-level threshold for selective neck dissection and excludes level I 5, 6
The procedure should include removal of lymph node levels II, III, IV, V, and VI, and may include preservation of nonlymphatic structures such as the sternocleidomastoid muscle, internal jugular vein, and spinal accessory nerve 5, 6