In glottic carcinoma with subglottic extension, which cervical lymph node groups should be evaluated and treated?

Lymph Node Evaluation in Glottic Carcinoma with Subglottic Extension

When glottic carcinoma extends into the subglottis, you must evaluate and treat the paratracheal (level VI) and pretracheal (Delphian) lymph nodes, in addition to the standard cervical lymph node levels II-IV, because subglottic involvement creates a distinct lymphatic drainage pathway to these lower neck and mediastinal nodes. 1, 2, 3, 4

Lymphatic Drainage Pattern Changes with Subglottic Extension

• Pure glottic carcinoma has sparse lymphatic drainage, and early-stage primaries rarely spread to regional nodes 5
• Subglottic extension fundamentally alters the metastatic pattern by engaging lymphatic channels that drain to paratracheal and pretracheal (Delphian) nodes, then secondarily to the jugular chain 1
• This altered drainage pathway explains the high incidence of stomal recurrences when paratracheal nodes are not addressed surgically 2, 4

Specific Lymph Node Levels to Include

Mandatory Nodal Levels

• Level VI (paratracheal nodes): Must be dissected bilaterally when any subglottic involvement is present 2, 3, 4
• Pretracheal (Delphian) nodes: Should be included in the dissection field 1
• Levels II-IV: Standard cervical lymph node levels remain at risk and should be addressed 3, 4

Levels with Lower Priority

• Level I: Has only 2.4% (95% CI 0-6.1%) incidence of occult metastasis in laryngeal cancer and should not be routinely included 6
• Level V: Has only 0.4% (95% CI 0-1.0%) incidence of occult metastasis and should not be routinely included 6
• Sublevel IIB: Has only 0.5% (95% CI 0-1.3%) incidence and should not be routinely included 6

Surgical Management Algorithm

• Perform total laryngectomy with hemithyroidectomy on the ipsilateral side when subglottic extension is present 2, 4
• If gross thyroid invasion is evident, perform total thyroidectomy 4
• Include bilateral paratracheal lymph node dissection (level VI) in all cases with subglottic involvement 2, 3, 4
• Ensure adequate low tracheal margin to prevent stomal recurrence 4
• The stomal recurrence rate is significantly higher (0.55% per month) when hemithyroidectomy and paratracheal dissection are omitted, compared to 0.07% per month when these procedures are included 2

Radiation Therapy Field Design

• Extend radiation fields to include both sides of the neck, the stoma, and the upper mediastinum to cover paratracheal lymphatic spread 3, 4
• Include the low and upper mediastinal compartments to address local/regional extralaryngeal involvement 3
• For supraglottic lesions with any subglottic component, use radiation fields ≥7 cm × 7 cm to encompass bilateral cervical lymphatics 7

Critical Diagnostic Pitfall

• Subglottic extension is frequently missed on preoperative evaluation—only 13 of 68 patients (19%) had correct preoperative diagnosis in one surgical series 2
• Routinely obtain CT imaging to estimate subglottic extension preoperatively, as clinical examination alone is inadequate 2, 3
• MRI can also be helpful for assessing the extent of subglottic disease 4

Why This Matters for Outcomes

• Subglottic carcinoma has poor overall 3-year survival (25%) due to high incidence of advanced-stage disease, extralaryngeal spread, and metastasis to lungs and paratracheal nodes 3
• Nodal involvement adversely affects survival rates in glottic cancer 5
• Failure to address paratracheal nodes results in significantly higher stomal recurrence rates 2, 4