Lymph nodal metastases in Head and neck cancer

Question 1

Draw the Diagnostic work-up flowchart for head and neck masses

Answer 1

[DRAW]

Question 2

Describe the 3 directions of lymphatic drainage of head and neck and detail the significance

Answer 2

Cranio -> caudal
Medio -> lateral
Superficial -> deep

It’s important to comprehend the lymphatic drainage direction to be able to image where the tumour is located and customize the surgical treatment

The Sub-mental, submandibular and para-tracheal nodes drain lymph into –> the deep jugular chain -> which drains into –> the Jugular lymphatic trunk (also drain spinal nodes) -> thoracic duct (left side) and right lymphatic duct (right side).

Damage to right lymphatic duct must be avoided during surgery on the 6th level

Question 3

Describe the superficial lymphatic system

Answer 3

The Superficial lymphatic system
- ~50-60 nodes on each side.
- Located over the fascia.
- Lymph from the skin and parotid gland
Skin, Lips, Tongue (anterior part), Oral cavity (anterior part) and Sub-mental region.
- Usually less affected by metastases.
- Drain into the deep jugular nodes

Question 4

Fully describe the deep lymphatic system

Answer 4

The Deep lymphatic system
Nodes that are found in the deep cervical part near the internal jugular vein (also called deep cervical lymph nodes).

The classification is done by levels.

A palatable node in the lower levels means that the metastases came from the head/neck region.
If the node is palatable in the first level, check the oral cavity, tongue, pharynx but not larynx.

Example: A thyroid tumor will never affect nodes in the 2nd and 3rd levels, treat the nodes starting from the 6th level.

Question 5

Describe the characteristics on palpation of a lymph node containing metastases

Answer 5

Firm, tender node that is adherent/fixed to the deep planes/fascia. Usually painless

Question 6

List the most common primary tumours which can give rise to head and neck metastasis

Answer 6

Upper Aerodigestive Tract 
Thyroid 
Salivary glands
Skin of the scalp, face and neck
Nasal and paranasal sinuses

Less frequently: lung and sub-diaphragmatic cancer

Question 7

After physical examination, describe the 1st level exam when you suspect lymph node metastasis

Answer 7

ULTRASOUND
Pros: Low cost, tolerable, and defines size
Cons: Not enough for staging, impossible to detect retropharyngeal nodes, operator dependant

US can be coupled by a FNAC (by radiologist)

Normal lymph-nodes will have:
• Oval shape
• Iso or hypoechoic pattern

Pathological lymph-nodes with metastasis will have
• Round shape
• Hypoechoic pattern
• Hyperechoic areas of necrosis

Question 8

When is FNAC very useful?

Answer 8

In cases of nodes with uncertain features (like when we don’t know where the primary tumour is)

Question 9

Fully detail the second level exams

Answer 9

CT SCAN

• Best technique for cancer staging (T and N)
• Detection of necrotic nodes
• Treatment planning
• Identification of deep lesions (that you cannot palpate)

A normal node will have:
•	Oval shape
•	Homogeneous pattern
•	Low-density (muscle-like)
•	Not peripheral enhancement

Size:
< 1 cm
<1.5 cm lymph-nodes of II and III level
<0.8 cm retropharyngeal lymph-nodes

A pathologic node will have:
•	Round shape
•	Central hypo-density area
•	Peripheral contrast enhancement
•	Size > 1 cm
•	Extracapsular spreading (sometimes)

MRI

MRI is asked mostly for cancer in the tongue area (here in Pavia)

• Better soft tissue contrast resolution than CT
• Used for T and N staging
• Better that CT for neurogenic lesions

A normal node:
T1
	Iso-intensity (muscle-like)
	Perinodal hyper-intensity (fat-like)
	Homogeneous

T2
 Hyper-intensity

A pathological node:
T1
 Hypo-intensity
 With gadolinium: hypo-intensity

T2
 Hyper-intensity
 Fat-suppression
 Good evaluation of necrotic areas

Question 10

Why is PET-CT not routinely used?

Answer 10

• It’s Expensive
• There are areas of physiological uptakes
• False positives due to inflammation after CHT-RT
• Micro-metastases (<7 mm) not detectable

However is can be used in follow up

Question 11

Which head and neck cancers are the most lympho-philic? What does this mean?

Answer 11

These lympho-philic tumours usually already have lymph-node metastasis at the time of diagnosis (%):

o	Nasopharynx (86%)
o	Hypopharynx (70%)
o	Oropharynx (60%)
o	Oral cavity (55%)
o	Supra-glottis (50%)
o	Glottis (<10%)
o	Maxilla (<10%)

Question 12

Compare N0 to N+ patients

Answer 12

N in TNM stands for nodes, therefore N+ patients have lymph node metastasis. The presence of Lymph node metastases is one of the most important prognostic factors

Two year disease free survival:
N0 = 87%
N+ = 75%

Also
o 25% of N+ patients will have recurrence of disease
o 25% of N+ patients have distant metastases
o 50% of N+ patients will have diffusion of the disease to soft tissues and lymphatic vessels

Question 13

Detail the classification of neck dissections

Answer 13

Everything can be cut except the carotid;
The jugular vein can be cut but just on one side.
In neck metastases the first-line treatment is always surgery.

1. Classical radical neck dissection (RND)
   Everything is cut (jugular vein, spinal nerve, sternocleidomastoid, etc.) except the carotid.
2. Extended radical neck dissection
3. Modified radical neck dissection (MRND)
   o Type I: spinal nerve spared
   o Type II: spinal nerve and sternocleidomastoid muscle (SCM) spared
   o Type III: spinal nerve, SCM and internal jugular vein spared
4. Selective neck dissection (SND) - The exact level involved has to be known:
   o Supra-omohyoid type (I-III)
   o Lateral type (II-IV) (Used in case of laryngeal tumor)
   o Posterolateral type (II-V)
   o Central compartment type (VI)
5. Neck dissection SSND (super-selective neck dissection)
   o Definition: complete removal of the fibro-fatty tissue contents including lymph nodes along the defined boundaries of 1 or 2 contiguous neck levels
   o Rationale: do not spare levels where metastases are less frequent BUT manage levels where metastases are more often present