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Invasion of the Vagus Nerve
Measures of disease extent that cannot
be identified and applied to clinical
staging should not be considered as staging
elements. One does not generally perceive
involvement of the vagus nerve clinically
unless its recurrent branch (that is,
the recurrent laryngeal nerve) is affected,
in which case the involvement is readily
detectable. Recurrent laryngeal nerve
symptoms are often due to mediastinal
lymph node metastasis, although they
can be due to primary tumor invasion.
It is important to note, however, that
(1) recurrent laryngeal nerve involvement
usually indicates inoperability and (2)
the survival for such patients is similar
to that for the IIIB-T4 stage group.
Accordingly, we recommend a T4 classification
for tumors with evidence of recurrent
laryngeal nerve involvement.
Great Vessels
Tumor involvement of the great vessels
is classified T4. The following are defined
as "great vessels":
- Aorta
- Superior caval vein
- Inferior caval vein
- Main pulmonary artery
- Intrapericardial
portions of the trunk of the right
or left pulmonary arteries
- Intrapericardial portions
of the superior or inferior right
or left pulmonary veins. More distal
branches
of
the main arterial and venous trunks
would be classified
T3
By virtue of the prognosis and treatment
options associated with vena caval syndrome
and esophageal and tracheal compression,
these manifestations indicate Stage
IIIB, not IIIA disease. It would be contradictory to the T4 definition to routinely
assign an N2 classification to these indications of disease extent. In the rare
instance of a peripheral primary tumor that clearly is not in direct continuity
with great vessels, evidence of compression of these structures may be caused
by nodal disease. The T and N categories
are then classified according to the established rules for these descriptors.
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