83

Central neck lymph node dissection



is an important component in the



treatment of papillary thyroid cancer.









Rebecca Kinkead. Nadav and Sara (detail), 2009. Oil and alkyd on canvas, 45 × 37 .









Central Neck Dissection for Papillary Thyroid Cancer

David T. Hughes, MD, and Gerard M. Doherty, MD



Background: Central compartment lymph node dissection is a common adjunct to thyroidectomy in the treatment

of papillary thyroid cancer. The indications, surgical technique, potential benefits, and operative risks of this

procedure should be clearly defined in order to provide optimal care to these patients.

Methods: A systematic review of the literature and an analysis of evidence-based recommendations were performed

regarding central neck node dissection for patients with papillary thyroid carcinoma.

Results: Cervical nodal metastasis in papillary thyroid cancer is a common occurrence. The presence of metastasis

is associated with increased recurrence rates and may decrease survival. Detection of central and lateral neck

nodal metastasis preoperatively with clinical examination and cervical ultrasound is important in determining

the appropriate initial surgical management. Level VI neck dissection and central neck dissection are terms

often used interchangeably to describe surgical excision of all lymph nodes from the hyoid bone to the sternal

notch between the carotid arteries, but the addition of the superior mediastinal lymph nodes in compartment

VII should be included in the central neck dissection. Due to improved recurrence rates and survival, therapeutic

central neck dissection is recommended for all patients with nodal involvement detected pre- or intraoperatively.

Prophylactic central neck dissection in patients without detectable nodal disease remains a controversial topic due

to a lack of definitive evidence of improved recurrence rates or survival and the possibility of higher complication

rates compared to total thyroidectomy alone. Reoperative central nodal dissection can be a challenging procedure

with increased complication rates but with good outcomes in experienced centers.

Conclusions: Central neck lymph node dissection plays an important role in the appropriate treatment of papillary

thyroid cancer at initial presentation and in cases of recurrent disease. Surgeons caring for this group of patients

should have familiarity and skill with this procedure.



Introduction

Papillary thyroid cancer is the most common form of

differentiated thyroid cancer, comprising approximately

90% of the 44,670 estimated new cases of thyroid cancer

in the United States in 2010.1 The established primary treat-

From the Department of Surgery at the University of Michigan,

Ann Arbor, Michigan. Dr Hughes is now with Montefiore Medical ment of papillary thyroid cancer per American Thyroid

Center/Albert Einstein College of Medicine, Bronx, NY. Association (ATA) guidelines is total thyroidectomy

Submitted February 24, 2010; accepted April 16, 2010. for all tumors larger than 1 cm, while thyroid lobectomy

Address correspondence to David T. Hughes, MD, Montefiore Medical is sufficient for tumors smaller than 1 cm.2 The ATA

Center/Albert Einstein College of Medicine, 1400 Bainbridge Avenue, consensus statement also recommends therapeutic

Bronx, NY 10467. E-mail: dhughes@montefiore.org

central neck dissection in patients with clinically involved

No significant relationship exists between the authors and the com-

panies/organizations whose products or services may be referenced nodes and prophylactic central neck dissection in ad-

in this article. vanced primary tumors (T3 or T4) without evidence of



April 2011, Vol 18, No. 2 Cancer Control 83

nodal involvement.2 Radioactive iodine ablation plays an without central neck nodal involvement are rare but

important role in adjuvant treatment following thyroid- do occur.5,6 Patients with nodal metastasis have higher

ectomy for some subgroups of patients based on risk of rates of persistent and recurrent disease during postop-

recurrence.2 This treatment algorithm achieves extremely erative surveillance.6 The impact of nodal metastasis on

low death rates; however, the rates for cervical lymph overall survival remains debatable; several studies have

node metastasis and recurrence remain significant. De- demonstrated no difference in mortality, while two large

spite the ATA recommendations, there is controversy re- population-based studies have shown increased mortal-

garding the ideal surgical management of the central neck ity in patients with regional lymph node metastasis.7-11

lymph nodes in patients with papillary thyroid cancer.

Detection of Nodal Metastasis

Nodal Metastasis in Papillary Thyroid Cancer The initial approach to a patient with a thyroid nodule

Incidence and Relevance should include a detailed examination of the thyroid

Papillary thyroid cancer and the follicular variant of and the cervical lymph node compartments. The clas-

papillary thyroid cancer have a propensity for cervical sification system of cervical lymph node compartments

lymphatic spread that occurs in 20% to 50% of patients is well defined and is important not only in identifying

on standard review of surgical pathologic specimens and the location of pathologic lymph nodes, but also in plan-

in 90% of those examined for micrometastases.3,4 The ning surgical treatment as outlined and illustrated in the

spread of tumors cells occurs in a predictable pattern recent ATA guidelines for management of thyroid cancer

that initiates in the perithyroidal lymph nodes of the (Fig 1).2,12,13 Patients with papillary thyroid cancer oc-

central neck and progresses to the lymph nodes of the casionally present on initial assessment with palpable

lateral cervical compartments and the superior medias- cervical lymphadenopathy, which is most often located

tinum.5,6 “Skip” metastases to the lateral compartment in the central neck or levels III and IV of the lateral neck,

usually in conjunction with an ipsilateral thyroid nodule.

Cervical ultrasound, often performed as an office-

based examination, is the primary imaging modality for

the initial assessment as well as the postoperative sur-

veillance of patients with papillary thyroid cancer. High-

resolution ultrasonography can detect cervical nodal

metastasis in 14% to 20% of papillary thyroid cancer

patients and can detect pathologic nodes as small as

2 to 3 mm without the risks associated with radiation

exposure.14,15 Ultrasound is also easily repeatable and

has been shown to change the surgical procedure per-

formed in 39% of thyroid cancer patients.14,15 A dedicated

cervical ultrasound to include nodal levels II–VI should

be performed, ideally by a dedicated clinician such as

the thyroid endocrinologist, the operating surgeon, or a

radiologist with particular interest, to detect nonpalpable

lymph node metastases in patients undergoing surgical

evaluation for any thyroid nodule (Fig 2). The sensitivity









Fig 1. — Lymph node compartments of the neck. Level VI and VII are

included in central neck dissection, while lateral neck dissection typically

includes levels II–V for treatment of papillary thyroid cancer. From Ameri-

can Thyroid Association Surgery Working Group, American Association of

Endocrine Surgeons, American Academy of Otolaryngology-Head and Neck

Surgery, et al. Consensus statement on the terminology and classification Fig 2. — Ultrasonic appearance of level III lymph node with papillary thyroid

of central neck dissection for thyroid cancer. Thyroid. 2009;19(11):1153- cancer metastasis using 12.5 MHz linear transducer. Note the irregular border

1158. Courtesy of Mary Ann Liebert, Inc. of the lymph node and the lack of the normal hyperechoic hilar line.



84 Cancer Control April 2011, Vol 18, No. 2

of cervical ultrasound to detect pathologic lymph nodes the central neck dissection should be noted as this is

in papillary thyroid cancer patients is higher in the lateral often a site of persistent disease following central neck

neck (94%) than in the central neck (53% to 55%), and dissection. Moo et al19 compared ipsilateral vs bilateral

this disparity may be considered as additional support central neck dissection for papillary thyroid cancer and

for prophylactic central neck dissection.16 Pathologic concluded that an ipsilateral dissection was sufficient in

lymph node metastasis detected on ultrasound can be tumors less than 1 cm, while tumors larger than 1 cm

confirmed with ultrasound-guided fine needle aspiration. required bilateral central neck dissection based on the

In patients with suspected mediastinal disease or with high incidence of contralateral central neck disease in a

bulky cervical lymphadenopathy, cross-sectional imaging retrospective analysis of the pattern of nodal metastases in

with CT should be considered as it can aid in the plan- surgical specimens. Some additional studies demonstrat-

ning of nodal dissection and often identifies pathologic ed that ipsilateral central neck dissection was adequate for

level VI and VII lymph nodes within the superior medi- tumors larger than 1 cm.20 If lateral cervical metastases

astinum that are not detected on cervical ultrasound or are present in levels II–V, a bilateral central nodal dissec-

physical examination. tion should be included with the modified radical neck

dissection to remove the presumed central neck nodal

Operative Considerations for disease based on described patterns of nodal spread.21

Central Neck Lymph Node Dissection

Technique Complications

Cervical nodal dissection for papillary thyroid cancer Complications of central neck dissection include injury

should include a systematic or en bloc nodal basin dissec- to the recurrent laryngeal nerve or the external branch

tion rather than a selective or “berry picking” dissection of the superior laryngeal nerve, which occurs in 1% to

due to higher rates of persistent and recurrent disease 2% of patients based on several studies.20,22-25 Small retro-

with the later approach.17 The ATA consensus statement12 spective studies have shown that the addition of central

regarding the terminology and classification of the central compartment lymphadenectomy to total thyroidectomy

neck defines the central compartment nodal dissection for thyroid cancer has not increased nerve injury rates

as all perithyroidal and paratracheal soft tissue and lymph in experienced hands.20,22,23,26 In cases of reoperative

nodes with borders extending superiorly to the hyoid central lymph node dissection after either previous

bone, inferiorly to the innominate artery, and laterally thyroidectomy or central node dissection, reports have

to the common carotid arteries and is well described noted increased nerve injury rates ranging from 1% to

and illustrated by Grodski et al18 (Fig 3). The inclusion 12%.24,25,27-29 Temporary hypoparathyroidism following

of the level VII nodes in the superior mediastinum with central neck dissection occurs in 14% to 40% of cases

depending on the definition of hypoparathyroidism used

in the study.20,22,23,30-33 The higher incidence of tempo-

rary hypoparathyroidism is likely due to the increased

incidence of parathyroid reimplantation and inadvertent

inclusion of parathyroid glands in the nodal dissection.

Reports are mixed regarding the risk of permanent hypo-

parathyroidism. A meta-analysis of retrospective studies

reported a 1.2% incidence as defined by the requirement

for calcium supplements greater than 6 to 12 months

postoperatively; however, none showed a statistically

significant difference in total thyroidectomy with or with-

out central neck dissection.34



Situational Considerations

Therapeutic Central Neck Dissection

Pathologic lymph node involvement noted on preopera-

tive clinical or imaging assessment is a well-established

indication for therapeutic lymph node dissection.2 A

careful search for the presence of pathologic central com-

partment lymph nodes with both physical examination

Fig 3. — Right-level VI lymph node dissection including all perithyroidal

and paratracheal soft tissue and lymph nodes. Judicious use of parathyroid and cervical ultrasound is critical during preoperative

reimplantation should be utilized with regard to the lower parathyroid assessment. The presence of pathologic level VI lymph

glands. From Grodski S, Cornford L, Sywak M, et al. Routine level VI lymph nodes should prompt detailed physical and ultrasonic

node dissection for papillary thyroid cancer: surgical technique. ANZ J

Surg. 2007;77(4):203-208. Reprinted with permission of John Wiley and examination of the lateral cervical nodal chains for ad-

Sons, Inc. ditional evidence of metastasis. Suspicion of lymph node



April 2011, Vol 18, No. 2 Cancer Control 85

involvement can be confirmed with fine needle aspira- noninvasive tumors without nodal disease can forgo I131

tion biopsy. The surgical technique for therapeutic nodal ablation. The evidence to support prophylactic dissec-

dissection should include both the ipsilateral and the tion due to decreased recurrence rates and improved

contralateral central compartments. The lymph node survival is sparse and is primarily composed of a pro-

dissection specimen should be excised en bloc during spective population-based study from Sweden.47 This

thyroidectomy. Any incidental note of suspicious nodes study demonstrated that the rate of death due to thyroid

in the lateral neck should prompt biopsy and frozen sec- cancer, which ranged from 8.4% to 11.1%, was reduced to

tion analysis for confirmation of cancer involvement. If 1.6% in patients who underwent central neck dissection

cancer is present in any lateral neck nodes, the dissection compared to contemporary controls. However, several

should be extended to an ipsilateral modified radical neck retrospective cohort studies have shown no difference

dissection to include levels II–V.35-37 Liberal application or only a slight improvement in recurrence or survival

of parathyroid reimplantation during central neck dis- rates.36,48-50 While an additional benefit of reduced post-

section should be employed to prevent postoperative operative thyroglobulin levels after central neck dissec-

hypoparathyroidism.20 tion was demonstrated by Sywak et al,20 a recent study

There are several goals in the use of nodal dissection at our institution showed no difference in thyroglobulin

for clinically evident locoregional lymph node metastasis levels between total thyroidectomy or total thyroidec-

in papillary thyroid cancer. The primary intent is loco- tomy with central neck dissection.46 In patients with

regional control of disease, given the correlation of nodal known distant metastasis without evidence of cervical

metastasis with significant increases in persistent and nodal involvement, a prophylactic neck dissection to

recurrent disease.6,8,38,39 Several studies have demon- include both the central neck and the ipsilateral lateral

strated decreased recurrence rates and improved sur- neck has been recommended by some due to the high

vival when the burden of cervical disease is removed via rates of nodal involvement in this group of patients on

therapeutic neck dissection.15,33,40 In patients with known histological analysis.51 Overall, the addition of prophylac-

distant metastatic disease, the debulking of cervical dis- tic central neck dissection appears to provide important

ease for palliative purposes is beneficial in preventing staging information that can affect radioactive iodine

local complications. ablative treatment, but the evidence regarding recurrence

and survival benefits remains limited and conflicted.

Prophylactic Central Neck Dissection The arguments against prophylactic central lymph

Prophylactic or routine central neck dissection for pa- node dissection at the time of initial thyroidectomy for

tients with papillary thyroid carcinoma is defined as papillary cancer focus on the unproven benefit and the

complete excision of the level VI and VII lymph nodes possibility of increased complications. The relevance of

in patients with no evidence of nodal involvement after subclinical cervical lymph node metastasis on rates of

preoperative clinical and imaging evaluation. The role of recurrence and survival has been questioned by some ret-

prophylactic central neck dissection remains a conten- rospective studies.50 Additionally, there is a lack of proven

tious issue regarding its benefits and risks, and several benefit in outcomes after prophylactic central node dis-

reports have reviewed this subject.41-43 Several single- section. The possibility of increased complication rates

institution retrospective cohort studies on total thyroid- with central neck dissection has been addressed, although

ectomy alone vs with prophylactic neck dissection, as again by only small retrospective cohort studies.20-23,26,31,52

well as a meta-analysis of these studies, have reported Higher rates of temporary hypoparathyroidism with cen-

mixed results.20,22,23,30,31,34 tral neck dissection seem consistent between these stud-

Proponents of prophylactic central neck dissection ies, while the rates of permanent hypoparathyroidism

at the time of initial thyroidectomy cite the high inci- and nerve injury rates are statistically similar compared

dence of cervical lymph node metastasis and the associ- with total thyroidectomy alone.34,42 The debate on the

ated increase in recurrence rates with the possibility of role of routine central neck dissection in the treatment

decreased survival. The low sensitivity of preoperative of papillary thyroid carcinoma is likely to continue until

ultrasound evaluation and intraoperative assessment to a large randomized trial with long-term follow-up can

accurately detect lymph node involvement is also used be completed.

as rationale for routine central neck dissection.15,38,44

The addition of central neck dissection to initial total Reoperative Central Neck Dissection

thyroidectomy can provide valuable staging informa- Reoperative central neck dissection is defined as removal

tion and has been shown to upstage approximately a of all remaining soft tissue in the level VI and VII compart-

third of patients older than 45 years of age to stage III ments in a patient who has undergone previous thyroid-

disease in two retrospective reviews.45,46 This upstag- ectomy or central lymph node dissection. This is often

ing has important implications for further treatment as indicated for patients with papillary thyroid cancer who

those with nodal metastasis are likely to receive higher are noted to have central neck lymph node involvement

doses of I131 ablation treatment, while those with small, on surveillance examination or imaging studies after com-



86 Cancer Control April 2011, Vol 18, No. 2

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88 Cancer Control April 2011, Vol 18, No. 2