Neck, Cervical Metastases, Surgery Treatment & Management

In the N0 neck, no prospective studies demonstrate survival rate differences among patients who undergo surgical, radiation, and expectant management. In view of poor prognosis at the time of future relapse, persons with primary lesions with more than 20% likelihood of metastasis should undergo either surgery or radiation therapy at the time of primary treatment. Radiation therapy in the N0 neck reduces the recurrence rate to approximately 5%. The node-positive neck is more effectively treated with a combination of surgery and radiation. In patients with bulky nodal disease, a complete response in the neck to sequential chemotherapy and radiotherapy or radiotherapy alone may indicate that neck surgery is not necessary for good locoregional control and improved disease-free survival rates.^[14]

Comprehensive neck dissections include the RND and its 3 modifications (ie, RND, MND, SND).

Radical neck dissection

RND involves the removal of all lymphatics from the inferior border of the mandible to the clavicle between the lateral border of the strap muscles and the anterior border of the trapezius (removal of all soft tissue in levels I-V). The floor of resection is formed by the fascial plane of the scalene muscles and the levator scapulae. The SCM, the IJV, and the SAN are removed. Traditionally, RND was the only surgical method of treating the neck; however, with the encouraging results of the more limited modifications resulting in less morbidity, RND is no longer indicated in most cases, even in node-positive necks.

Modified radical neck dissection (Medina classification)

MND is based on the concepts that (1) an en bloc removal of the cervical lymphatics can be accomplished by stripping the fascia from the SCM and IJV, (2) no lymphatic communication was ever noted between these structures and the cervical lymphatics, (3) both the spinal accessory and the hypoglossal nerves do not follow the aponeurotic compartments but rather run across them; therefore, if the tumor does not directly involve the nerves, they can be spared and (4) shoulder dysfunction can be avoided.

Type I modified radical neck dissection: The procedure for the type I modified RND is the same as the RND except that the SAN is spared. This technique is used less commonly in the N0 neck, but it would be a reasonable choice with neck disease that involved the SCM or jugular vein without involving the SAN. The survival rate and the disease-free survival rate are not affected by preservation of the SAN. The pattern of failure is the same for the 2 procedures (ie, nerve preservation does not cause higher chances of recurrence).

Type II modified radical neck dissection: This surgery is the same as in the RND, but the SAN and IJV are spared. The type II modified RND is indicated in node-positive necks with metastatic involvement of the SCM but without involvement of the nerve and vein.

Type III modified radical neck dissection (functional neck dissection): Type III modified RND is similar to the RND with preservation of all 3 structures (ie, SAN, IJV, SCM). In many centers, this operation is popular in the treatment of hypopharyngeal and laryngeal tumors with N0 necks. Molinari, Lingeman, and Gavilan propose this procedure for N1 necks when the involved nodes are mobile and do not measure more than 2.5-3 cm. Bocca proposes this operation for any neck that has indications for an RND as long as the nodes are not fixed.^[2] The recurrence rates with functional neck dissection are similar to those associated with RND. See the image below.

Selective neck dissections

SNDs are based on recent understandings of lymphatic spread in the head and neck. Only those regions with high risk for metastasis are removed.^[7] The SND provides the same survival rate and/or disease-free survival rate and staging information as RND. Manipulation of the SAN is minimized in SNDs, although short-term (3-4 mo) reversible shoulder dysfunction can occur.^[15]

Types of selective neck dissection are as follows:

• Supraomohyoid (anterolateral) neck dissection: Levels I, II, and III are removed and the SCM, IJV, and SAN are spared. This dissection is indicated in the treatment of oral cavity lesions.
• Lateral neck dissection: Levels II, III, and IV are removed, sparing the SCM, IJ, and SAN. Lateral neck dissection is indicated in tumors of the larynx, oropharynx, and hypopharynx in a node-negative neck.
• Posterolateral neck dissection: Levels II, III, IV, and V are removed, sparing the SCM, IJV, and SAN. Posterolateral neck dissection is indicated in the treatment of skin tumors located in the posterior scalp or neck (eg, melanomas, SCCA, Merkel cell carcinomas).

Extended neck dissections

Any of the above dissections that encompass the removal of additional structures or other groups of lymph nodes are extended neck dissections. Retropharyngeal node involvement often occurs in tumors of the pharyngeal walls. Level VI excision is required in thyroid, tracheal, and postcricoid carcinomas. Tumor infiltration into the carotid artery, hypoglossal nerve, and levator scapulae muscles may warrant excision. Paratracheal and pretracheal nodes, vertebral transverse process, and mediastinal nodes removal may be necessary in some situations.

Perform a complete physical examination (especially head and neck), including evaluation of the patient's ability to open the mouth adequately for intubation, evaluation of the airway and dentition of the patient, and assessment of cardiopulmonary status.

Obtain medical clearance and recommendations. Instruct the patient to take regular medications until the midnight before the surgical procedure. Ensure that informed consent has been fully discussed with the patient. Explain the disease, treatment plan, possible complications, and alternative plans to the patient and relatives.

Order nothing by mouth (NPO) after midnight on the night before surgery is planned. Note order of premedication and preoperative antibiotics.

Airway

Performing a tracheotomy under local anesthesia is better if a difficult intubation is anticipated. For surgery within the oral cavity or through the oral cavity, nasal intubation is required. For nonoral surgeries or approaches, orotracheal intubation is preferred. Packing around the tube may prevent aspiration and leakage. In difficult cases, bronchoscope-assisted intubation is recommended.

If the surgery is prolonged or complex, insert a urologic catheter for better control of urine output.

Positioning

Place the patient in a supine position with a shoulder roll extending the neck. Pull the arm gently down and strap it to the side of body. Elevate the head end by approximately 30°. Rotate the head to the opposite side and push the chin upward to obtain maximum extension. Prepare and drape the patient's neck and upper chest in a sterile fashion for the surgery.

Incisions

Various incisions are available (eg, Crile, Hayes Martin, MacFee, hockey-stick). The incision used depends on the location of the primary tumor and whether surgery is planned for 1 or both sides of the neck. In making the incision, the surgeon should avoid trifurcation over the region of the carotid artery and narrow-based flaps. If an RND is to be performed alone, the hockey-stick incision is generally preferred. Mark the skin incision. Infiltration of the skin incision with 10 mL of lidocaine with 1:100,000 epinephrine minimizes bleeding. Make scratch marks with the back of the knife to assist in the alignment of the skin flaps at the end of the operation.

Flap raising

Make the skin incision through the platysma and elevate the flap in the subplatysmal plane. Traction with the surgeon's fingers and countertraction by the assistant with skin hooks are definitely required. Leave the greater auricular nerve and external jugular vein on the SCM while raising the superior lateral aspect of the flap. Elevate the posterior flap toward the trapezius muscle. Identify and preserve the marginal mandibular nerve at the superior aspect of the flap. This nerve passes within the fascia of the submandibular gland. A simple way to protect this nerve is to divide the common facial vein at the anterior border of the SCM muscle and to dissect the superior flap deep to this vein.

Dissection

Remove submental fatty tissue and displace it inferiorly. Retract the mylohyoid muscle to expose the lingual nerve, and submandibular duct. Ligate and cut the facial artery, submandibular duct, and mylohyoid vessels. Remove the submandibular nodes and the submandibular gland and sweep them down. Cut the SCM superiorly 1 cm from the mastoid to expose the posterior belly of the digastric muscle. Expose the SCM and incise it just above the clavicle. Identify the anterior and posterior belly of the omohyoid and transect. Identify the IJV, carotid, and vagus nerve in the lower aspect of the neck. Ligate IJV in case of classic radical dissection or type 1 modified dissection.

Open the supraclavicular fatty tissue and identify the phrenic nerve and brachial plexus. Preserve the phrenic nerve and brachial plexus. Once the brachial plexus is visualized, clamp the fibrofatty tissue with a large clamp. The SAN is sacrificed in the RND, but in an MND, the nerve has to be traced while raising the lateral skin flap and while dissecting laterally. Continue the dissection along the anterior border of the trapezius. Follow the cervical branches and section them high on the specimen. Separate the specimen from the carotid, vagus, and hypoglossal while proceeding superiorly. Preserve the superior thyroid artery and superior laryngeal nerve. Identify the IJV superiorly and ligate. Achieve good hemostasis and insert vacuum drains, 2 for each side of the neck. Close the wounds in layers (ie, platysma followed by skin).

A liquid or light diet is allowable a few hours after surgery if none of the structures allowing the patient to protect his or her airway or allowing deglutition has been violated. An appropriately longer period may be needed if the neck dissection is combined with more extensive surgical procedures (eg, 7-8 days NPO if pharynx has been opened and flap inserted).

Maintain head elevation at a 30° angle. Monitor vital signs and intake and output every 4 hours. Watch for bleeding or hematoma formation. Watch for fistula formation if the thoracic duct was damaged intraoperatively or the pharynx was opened accidentally. Maintain constant humidification, suctioning, and cleansing of the tracheotomy tube. Make sure that the Hemovac or suction drains are functioning properly and the drains do not clot. Administer antibiotics per hospital protocol and pain medications as needed. Encourage early ambulation with assistance and deep breathing exercises.

Discharge criteria

Discharge is appropriate once the suction and drains have been removed (usually fourth to fifth postoperative day) and the wound has healed satisfactorily. No evidence of bleeding or infection should be present. An adequate airway and nutrition must be established. Adequate family and/or home care support are also necessary.

Physical therapy for the shoulder is initiated prior to discharge and continued at home. Review the patient's status after 7 days.

Check the pathology report for complete or incomplete resection and carcinoma-free margins and plan adjuvant treatment (ie, radiation therapy and/or chemotherapy). Remove sutures or clips at day 7, except when radiation therapy has been administered.

Long-term follow-up care should include monitoring for a recurrent tumor or development of a second primary. The patient should be seen every month for the first year. Continue follow-up every 2-4 months for up to 5 years. After this interval, the patient may be seen yearly.

For excellent patient education resources, visit eMedicine's Cancer and Tumors Center. Also, see eMedicine's patient education article Cancer of the Mouth and Throat.

Neck dissections are safe operations with remarkably low mortality and morbidity.

The advantages of MND are preservation of neck and shoulder function, improved cosmesis, and protection of the ICA; also, the procedure may potentially be performed bilaterally simultaneously.^[2] MND offers the same survival and disease-free survival benefits as classic RND.

Factors predisposing to complications include the following:

• Composite resection of mucosal areas
• Previous radiation therapy
• Advanced age
• Poor general health
• Systemic illness
• Chronic malnutrition
• Smoking
• Alcoholism
• Diabetes mellitus

Intraoperative complications

• Hemorrhage: Hemorrhage is an uncommon complication if careful attention is paid to anatomy and hemostasis with the electrocautery unit. Injury to the carotid during surgery should be repaired immediately. If excessive bleeding occurs from the lower end of the jugular vein, apply pressure followed by adequate suctioning until the stump is visualized and ligate properly. If the bleeding occurs from the upper end of the vein and the stump is not visualized, then packing the jugular foramen with large pieces of Surgicel and/or plicating with the posterior belly of the digastric muscle controls the bleeding.
• Hypotension: Hypotension occurs when dissecting around the carotid bifurcation (carotid sinus reflux). This may be avoided with careful dissection at the carotid bifurcation without manipulation. Local spray or injection of 2 mL of local anesthetic into the adventitia at the carotid bifurcation may help.
• Pneumothorax: Pneumothorax is a very rare complication when dissection involves paratracheal nodes and base of the neck areas. It involves a sudden compromise of the respiratory and circulatory system. If the pneumothorax is small, airtight closure of the wound usually controls the situation. A large pleural leak requires immediate placement of a chest tube with an underwater drainage.
• Air embolus: An air embolus can occur when a large vein is inadvertently opened and a large volume of air enters rapidly into the open vein by negative pressure and passes directly into the right atrium. Clinically, hypotension and cyanosis suddenly appear, the peripheral pulse disappears, and a loud churning noise is heard over the precordial area. The treatment involves immediate clamping of the offending vein and turning the patient onto the left side with the head down. Prevention is best, with careful identification, adequate ligations, and transfixion sutures.
• Nerve damage: With nerve damage, a loss of sensation occurs in multiple areas, including the neck, posterior occiput, external ear, mandibular region, lateral shoulder, deltoid area, and upper pectoral area. The marginal mandibular nerve is preserved unless it is involved by metastatic disease. Its damage results in lower lip weakness. The sacrifice of the cervical sympathetic chain produces Horner syndrome. The removal and/or damage of the SAN produces shoulder drop, limitation in the range of motion of the arm and shoulder, and pain in the affected areas. Most patients improve markedly with physical therapy. Unilateral resection of the hypoglossal nerve is usually well tolerated, but bilateral hypoglossal nerve resection causes severe difficulty in feeding, swallowing, and speaking. Resection or injury to the lower or middle neck of the vagus nerve causes vocal cord paralysis. Injury to the brachial plexus is a complication that should be avoided by proper identification of anatomic planes.
• Thoracic duct injury: Thoracic duct injury can occur with dissection of the region of the thoracic duct, particularly on the left side. If it occurs, ligate the thoracic duct. Ask the anesthesiologist to apply positive pressure to reevaluate whether leaking is present. If leak persists, then apply more sutures.

Postoperative complications

Patients who have received radiation therapy prior to RND are prone to have increased postoperative complications (eg, wound infection, fistula, flap necrosis, osteoradionecrosis, carotid artery rupture). Few institutions reserve surgery for salvage after unsuccessful radiotherapy in the treatment of cancer of the head and neck.

• Hematoma: Meticulous hemostasis and the use of suction drains are the best ways to avoid a hematoma. A hematoma is evident by accumulation of blood under the flap in the first few hours after the operation. Reexploration, evacuation of the hematoma, ligation of the offending vessel, irrigation, replacement of drains, and resuturing are essential.
• Wound infection: While a wound infection is very unlikely when RND is performed alone, it usually occurs in association with en bloc mucosal resection. Other predisposing factors to wound infection are previous irradiation, ischemia, malnutrition, chemotherapy, anemia, diabetes mellitus, and advanced tumor mass. Prompt debridement and infection control measures are required.
• Skin flap loss: Skin flap loss is a consequence of poor vascularity, errors in design or elevation, underlying hematoma, preexisting scars, infection, and poor nutrition. If the carotid artery is not exposed, then a conservative approach in the form of careful trimming of necrotic tissue and regular wound dressings is sufficient. If the carotid artery is exposed, then coverage is needed. The flaps used include the deltopectoral, pectoralis major, and trapezius.
• Salivary fistula: Salivary fistula occurs when the oral cavity and pharynx have been opened. The fistula appears within 4-5 days of surgery. It may appear as a small leak and is usually managed with conservative measures.
• Chylous fistula: A chylous fistula appears within 24-48 hours and can be identified by the appearance of a milky fluid in the drains. If it is minimal, it can be controlled by aspiration, pressure dressings, and a fat-free diet. When the leak is extensive (>500 mL of drainage), ligation of the offending thoracic duct is required.
• Facial edema: Facial edema is more commonly observed in patients with previous irradiation. Ipsilateral involvement occurs with unilateral neck dissection (especially with removal of the IJV). Facial edema reaches a maximum at postoperative days 5 and 6, followed by a progressive decrease in a few weeks. Bilateral resection of IJVs at the same time results in massive facial edema. Airway management with a tracheotomy may be required. With cerebral edema, the increase of intracranial pressure can cause neurologic deficit and even coma.
• Electrolyte disturbances: Hyponatremia is the most common postoperative electrolyte disturbance. It is usually dilutional or, in some individuals, is due to inappropriate secretion of antidiuretic hormone. It is manifested by altered behavior, restlessness, and hallucinations.
• Carotid artery rupture: The frequency of this complication ranges from 3-7%. It is observed in patients who have undergone RND with resection of mucosal areas. Prior radiation therapy, infection, flap necrosis, and salivary fistula are some of the predisposing factors. Apply direct and firm pressure and, if the bleeding cannot be controlled by pressure, clamp the common carotid artery as an emergency procedure and avoid repair or diversion in an area of infection. If a salivary fistula is present, attempts should be made to divert it. Cover the carotid artery with the levator scapulae or posterior scalene muscle.

Cervical metastasis is the single most important prognosticator in head and neck SCCA, and its presence indicates a roughly 50% reduction in the overall survival rate. The prevalence of lymphatic spread is greater than 20% for most of the SCCAs of the head and neck. A neck with histologically negative findings has a recurrence rate of 3-7%, and in contrast, a neck with histologically positive findings has a recurrence rate of 20-70%. Prognostic factors of cervical metastasis are site, size and number of metastatic nodes, and extracapsular spread.

Those patients with involvement beyond the first echelon of lymphatic drainage have a poorer prognosis (eg, a very low survival rate is observed if level V is involved in nonnasopharyngeal tumors). Posterior triangle and contralateral involvement are also indications of a poor prognosis.

The number of involved nodes significantly impacts the survival rate, with involvement of 2 or more nodes carrying a much higher frequency of distant metastasis and local recurrence. Involvement of several nodes (4 or more) is associated with a worse prognosis than involvement of only one node. Multiple levels of involvement are associated with a recurrence rate of 70%; only 1 level of involvement has a recurrence rate of 35%. A correlation exists between size and perineural and perivascular infiltration of the tumor.

Extracapsular spread is commonly found in 25% of small nodes and 75% of large nodes. It decreases the survival rate and the disease-free interval by one half. Macroscopic extracapsular spread has a recurrence rate of 45%, and microscopic spread has a recurrence rate of 25%.

Perineural and perivascular invasions are associated with more aggressive tumor behavior. Involvement of the tumor margins carries a poor prognosis and a high risk for recurrent neck disease. Node fixation, especially to the carotid artery or a muscle, is an ominous sign. Fixation occurs with large masses and denotes a poor prognosis. Degree of differentiation is a prognostic factor of cervical metastasis; poorly differentiated tumors are more aggressive and carry a poor prognosis. Lymphoid cell reaction and recurrent disease are other prognostic factors.

Sentinel node biopsy

Sentinel node biopsy was introduced in 1977 by Cabanas and has been worked upon since 1990, primarily in breast cancers and melanoma. Sentinel lymph node biopsy has not yet gained popularity in oral and oropharyngeal cancers. In recent years, however, a few multicenter trials and meta-analyses have reported positive results. These have encouraged many centers around the world to further research this aspect.

According to the sentinel node biopsy philosophy, if the first draining node of a primary has micrometastasis, the rest of the nodes are very likely to be affected. This is irrespective of lymphatic drainage of the site, however unconventional it may be. The procedure involves lymphoscintigraphy after the injection of radiocolloids, prior to the surgery. During surgery, a patent blue dye is injected to visually mark the node. Thereafter, an incision of the biopsy is taken and the node is traced by a gamma probe. This gamma probe is fitted with a collimator to exclude radiation from everywhere accept a small area. The identified node is dissected and sent for histopathogical examination and immunohistochemistry. If the sentinel node is found to be positive, a neck dissection is performed.

A multicenter trial (Ross et al) conducted from 1998 to 2002 reported sentinel node procedures in 227 patients of head and neck carcinoma.^[10] Of these 227 patients, 134 patients had T1/T2 lesions of the oral cavity and oropharynx. The sensitivity in these 134 patients was 93%. The study concluded that sentinel node biopsy can be used alone as a staging tool for oral and oropharyngeal squamous carcinomas. Some authors have reported 100% sensitivity.^[11] Hart et al reported 100% negative predictive value for SNB.^[12] However, the study involved only 20 patients. Paleri et al conducted a meta-analysis of sentinel node biopsy reports on 301 patients of the oral cavity and 46 patients of the oropharynx.^[13] This meta-analysis showed that the cumulative pay off for sentinel node biopsy alone as a staging procedure was 1% less than those with elective neck dissection in terms of recurrence and mortality rates. Identification rates with radiotracer dye was 97%.

Choice of colloid

Two colloids are commonly used for lymphoscintigraphy in Europe: Albures and

Nanocoll. Albures has a mean particle size of 500 nm and is a slower-moving particle that remains in first echelon (sentinel) nodes but requires a high density of terminal lymphatic vessels at the injection site. For this reason, Albures is the colloid of choice in the tongue and floor of mouth. Nanocoll has a mean particle size of 50 nm and is a faster-moving colloid that finds lymphatic vessels despite injection into tissues with low densities of terminal lymphatics. However, it moves readily from sentinel nodes to subsequent echelon nodes and for these reasons Nanocoll is the colloid of choice in primary tumors that aren’t located in the floor of the mouth or the tongue.

Biopsy procedure

• During surgery, 1-2 mL of patent blue V dye is injected throughout the normal mucosa and submucosa that surrounds the tumor. This should be performed prior to the skin incision. Ensure that the same injection sites are used for Patent blue V and the radiocolloid.
• The primary tumor is removed with adequate margins. In case the primary tumor is not excised first, the problem of the scattered radiation from the primary tumor can be avoided by using lead plates and a well-collimated detector gamma probe.
• A suitable small incision is made in the neck in accordance with the marking done by the nuclear physician.
• After cutting the deeper layers, a hand-held gamma probe is used to identify radioactive sentinel nodes. To reduce "shine through," a series of malleable, sterilized lead plates may be used to mask the injection site.
• Radioactive nodes are excised and radioactivity within the node is confirmed ex vivo.
• Blue stained lymphatic pathways are followed to the first draining lymph, which is harvested. Sentinel nodes are labeled according to their color and radioactivity.
• The anatomical level of sentinel nodes is noted.

Pathology

Sentinel nodes are fixed in 10% neutral buffered formalin and, after fixation, are bisected through the hilum, if this is identifiable, or through the long axis of the node. If the thickness of the halves is more than 2 mm, the slices are further trimmed to provide additional 2 mm blocks. If the sentinel nodes are found to be free from tumor on initial histological examination, step-serial sections are prepared at an additional 6 levels in the block at approximately 150 μm intervals. One hematoxylin and eosin stained section is prepared at each level. If the nodes still appear histologically negative, an immediately adjacent section from each level is examined by immunocytochemistry, using the multicytokeratin antibody.

Management of the neck following organ preservation protocols

The management of neck has evolved over the last few decades, owing to the morbidity of radical procedures, better understanding of the patterns of spread, and the successful introduction of chemoradiotherapy protocols. With the advent of organ preservation protocols for advanced head and neck cancers, the role of neck dissection has been primarily restricted to the adjuvant setting. Adjuvant neck dissection is typically performed after completion of chemoradiotherapy regimen, either as a part of planned neck dissection irrespective of neck response (usually 6-10 wk posttreatment) or as a salvage surgery for residual neck disease.

Although consensus states that N1 neck disease does not mandate a adjuvant neck dissection, controversies persist for N2/N3 neck disease treated with organ preservation protocols. Proponents of adjuvant neck dissection have shown a higher rate of regional failure and detrimental survival in patients who do not undergo neck dissection.^[16] Approximately 25%of patients who achieve complete response and subsequently undergo a planned neck dissection have persistent disease in the surgical specimen. Alternatively, 30-40% of partial responders who undergo a neck dissection show no viable disease. Hence, the accuracy of neck assessment using conventional clinical and radiological yardsticks is only 60%.^[17]

Nuclear imaging using PET-CT scanning has improved the accuracy of assessment in the postchemoradiotherapy setting. Studies have shown PET-CT scanning has a high negative predictive value (as high as 100%),^[18] thus making adjuvant neck dissection unnecessary in all cases of N2/N3 disease. A negative PET scan result is a fairly accurate indicator that the neck does not harbor any residual disease. However, a positive scan finding does not necessarily signify persistent disease. Most studies recommend 8-12 weeks as the optimal time for response assessment to reduce the chances of false positive results.

The consensus statement on the management of neck after chemoradiotherapy recommended observation of patients with initial N1 and N2 disease who achieved complete response after chemoradiotherapy. The complete response rate reduces from 80% for N1 nodes to about 40% for N3 nodes. Thus, in patients with N3 neck nodes, close observation may be advocated only in patients with a negative PET-CT scan finding.^[19] Assessment of partial responders appears to be more complex, with as many as 60% having pathologically negative neck nodes on adjuvant neck dissection despite using stringent radiological criteria. Hence, neck dissection may be unnecessary in almost two thirds of this group.

Although PET-CT scanning is an invaluable tool in this scenario, the cost of this investigation limits its use in basic resource settings. Ultrasonographic-guided fine-needle aspiration cytology (FNAC) may be a viable alternative in this setting.^[20] van der Putten et al reported a sensitivity as high as 80% with ultrasound-guided FNAC. Although the cytological features of nodes after chemoradiotherapy have not been extensively studied, the presence of viable tumor cells rather than necrotic cells could guide decision-making in this scenario.^[21]