Classification of neck node levels
• Robbins Classification:
• In 1991 the AAO-HNS classified neck lymph nodes into levels, based on surgical neck dissection
• This classification distinguishes six levels:
IA, submental lymph nodes
IB, submandibular lymph nodes
II, upper jugular lymph nodes
III, middle jugular lymph nodes
IV, lower jugular lymph nodes
V, posterior triangle lymph nodes
VI, anterior compartment lymph nodes
Limitations of using Robbins classification for
lymph node delineation in RT
• considers only those lymph nodes that are removed during neck dissections.
• lymph nodes not commonly removed, such as retropharyngeal, parotid, buccal, and occipital nodes,
are not included.
• L.n boundaries based on surgical procedures are not always easily identifiable on CT scans
• Moreover, in radiotherapy the neck is immobilized without rotation of the head, while in surgery the
position of the neck can be rotated which changes some of the boundaries
L.N classification based on Anatomico-radiological Boundaries
• With the introduction of CT and MRI need was felt to transfer the anatomical
boundaries of lymph node stations as described by surgeons onto CT scans
• several atlases of cross-sectional radiological anatomy of lymph nodes developed
Nowak and Levendag (Rotterdam) (1999)
Gregoire (Brussels) (2000)
DRAWBACK IN THE ANATOMICO-RADIOLOGICAL CLASSIFICATION
• All guidelines presented some differences in terms of
boundaries and sizes;
• consequently, the need was felt to unify terminology and
recommendations for contouring.
• The main differences between concerned the definition of
the cranial edge of levels II and V, the posterior edge of
levels II, III, IV, and V, and the caudal edge of level VI.
• At the end of 2003, the group published its “consensus guidelines” which have been
endorsed by the major European and American scientific societies
(RTOG, EORTC, GOERTEC, NCIC, and DAHANCA)
• In 2003, a consensus guidelines for node negative patients
• In 2006, these guidelines extended to include node positive and post-
• Although it appears that these recommendations are well accepted they
are also associated with some shortcomings
Shortcomings of previous consensus guideline
• not all the neck node areas described in the TNM atlas were included especially
lower and posterior neck , face, the scalp & base of skull
• description of the anatomic boundaries of some of these was not sufficiently
• guidelines for the node-positive neck,& ECE was arbitrary and imprecise in terms
of extension into normal structures to generate CTV
• Illustrations of the nodal levels were not available in DICOM consequently limiting
the easy use of the atlas
• Hence a task force was formed to review and update the previously published
guidelines on nodal level delineation
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