Karsinoma Laring

01Pathophysiology

The larynx is divided into three anatomic subsites, and understanding this division is the single most important concept for exam questions on this topic. The supraglottis includes the epiglottis, aryepiglottic folds, false vocal cords, and the ventricle. The glottis includes the true vocal cords, the anterior commissure, and the posterior commissure. The subglottis extends from the undersurface of the true vocal cords to the inferior border of the cricoid cartilage.

Each subsite has a different lymphatic drainage density, and this directly determines the natural behavior and prognosis of the tumor. The glottis has virtually no lymphatic drainage. This is why glottic carcinoma rarely presents with cervical nodal metastasis and carries the best prognosis of the three subsites. In contrast, the supraglottis has a rich bilateral lymphatic network, which means supraglottic tumors frequently metastasize to bilateral cervical lymph nodes, even at early stages. Subglottic tumors drain to paratracheal and pretracheal nodes, though this subsite is rare (fewer than 5% of cases).

The pathophysiology also explains the presenting symptom pattern. The glottis is where phonation occurs. Even a small lesion on a true vocal cord disrupts its vibratory edge, producing early hoarseness. This is why glottic tumors are caught early. Supraglottic tumors, however, do not directly affect the vocal cords in early stages. Their initial symptoms are vague: mild sore throat, a globus sensation, or dysphagia. A classic and frequently tested presentation of supraglottic cancer is referred otalgia without otoscopic abnormality. This occurs because the supraglottis shares sensory innervation with the ear through the internal branch of the superior laryngeal nerve (a branch of the vagus) and Arnold nerve (auricular branch of the vagus). Subglottic tumors are essentially silent until they grow large enough to obstruct the airway, presenting as progressive stridor.

Over 95% of laryngeal carcinomas are squamous cell carcinoma, arising from the squamous epithelium lining the laryngeal mucosa. Chronic exposure to tobacco smoke and alcohol produces repeated mucosal injury, leading to a progression from hyperplasia to dysplasia to carcinoma in situ to invasive carcinoma. Smoking and alcohol have a multiplicative (synergistic) carcinogenic effect, not merely additive, making the combination far more dangerous than either alone.

02Classification and Clinical Manifestation

By Anatomic Subsite

TNM Staging (Glottic, most commonly tested)

The single most tested staging concept is that vocal cord fixation automatically upgrades the tumor to at least T3, regardless of tumor size. This finding changes the management approach from radiation alone toward combined modality therapy.

03Diagnostic Workup

Any patient presenting with hoarseness lasting more than 3 weeks, particularly a smoker or heavy alcohol user, requires direct visualization of the larynx. The best initial test is flexible nasolaryngoscopy performed in the clinic. This allows real-time assessment of the mucosal surface, tumor extent, and critically, vocal cord mobility. Cord mobility is not just a diagnostic detail; it determines T staging and dictates the treatment plan.

If a lesion is identified, the next step is direct laryngoscopy under general anesthesia with tissue biopsy. This is the gold standard. It provides histopathologic confirmation and allows a thorough examination of the entire upper aerodigestive tract, because patients with one squamous cell carcinoma of the head and neck are at risk for synchronous second primary tumors (the concept of "field cancerization"). Panendoscopy (laryngoscopy, esophagoscopy, bronchoscopy) is performed at this time.

Once the diagnosis is confirmed, CT of the neck with IV contrast is the primary imaging modality for locoregional staging. It evaluates the depth of invasion, thyroid cartilage involvement, pre-epiglottic space extension, and cervical nodal status. Nodes are considered pathologic when they measure over 1 cm in short axis, show central necrosis, or exhibit irregular enhancement. MRI is used as an adjunct when cartilage invasion is equivocal on CT, as MRI provides better soft tissue contrast.

A CT of the chest is performed to evaluate for pulmonary metastases, which represent the most common site of distant spread. PET-CT is reserved for advanced disease (stage III/IV) or when distant metastasis is suspected.

04Management and Treatment

Early-stage glottic carcinoma (T1-T2, N0) is one of the most curable solid malignancies. Both radiation therapy and transoral laser microsurgery (TLM) achieve cure rates above 85%. The choice between them depends on institutional expertise and the patient's priorities regarding voice quality. Radiation is delivered over 5-7 weeks. TLM has the advantage of being a single-session outpatient procedure with preserved voice in most cases and leaving radiation as a salvage option.

For intermediate and advanced laryngeal carcinoma (T3 and selected T4a), the landmark organ preservation trials established that concurrent chemoradiation with cisplatin can preserve the larynx without compromising overall survival compared to total laryngectomy. The standard regimen is high-dose cisplatin at $100mg\mathrm{/}{m}^{2}100\backslash \; mg/m^2$ on days 1, 22, and 43 of a 7-week course of definitive radiation therapy (total dose approximately 70 Gy). If the patient cannot tolerate cisplatin (e.g., renal insufficiency with , hearing loss, neuropathy), alternatives include carboplatin or cetuximab, though cisplatin remains the standard of care.

Total laryngectomy is reserved for T4a tumors with frank cartilage destruction (where organ preservation is not appropriate) and for salvage after failed chemoradiation. After total laryngectomy, the patient breathes through a permanent tracheostoma. Voice rehabilitation is achieved primarily through tracheoesophageal puncture (TEP) with a one-way valve, which is the most effective method. Esophageal speech and electrolarynx devices are alternatives.

Contraindications and considerations: In patients with poor renal function, cisplatin must be replaced. In patients with a second primary or field cancerization, careful surveillance of the entire aerodigestive tract is needed. Patients treated with radiation for early glottic cancer require close follow-up with laryngoscopy every 1-3 months in the first two years, as early detection of recurrence allows salvage laryngectomy with good outcomes.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The most common way students get this topic wrong is by failing to connect the anatomic subsite to the clinical behavior. When a vignette describes a patient with early hoarseness and no palpable neck mass, students sometimes do not recognize that this points to a glottic primary with an excellent prognosis. Conversely, when a vignette describes referred otalgia, dysphagia, and bilateral cervical nodes, students may not realize this points to a supraglottic primary with a higher stage at presentation.

A second frequent trap involves vocal cord fixation. A vignette may describe a "small tumor" on the vocal cord, but then mention that the cord is immobile on examination. Students who focus on tumor size and call it early-stage disease will miss that cord fixation automatically makes this at least T3, which shifts the management from radiation alone toward chemoradiation or surgery.

The third trap relates to referred otalgia. A patient with ear pain and a normal otoscopic examination should raise suspicion for a head and neck malignancy, not an ear problem. Students who pursue an otologic workup instead of examining the larynx and pharynx will miss the diagnosis entirely.

Finally, students confuse the role of total laryngectomy in the modern era. The tested concept is that organ preservation with concurrent chemoradiation is the standard approach for T3 and selected T4a laryngeal cancer, and total laryngectomy is reserved for cases with cartilage destruction or as salvage for chemoradiation failure. Choosing upfront total laryngectomy for a T3 tumor when organ preservation is an option is a common wrong answer.

The core competency being tested is the student's ability to localize a tumor within the larynx based on symptom pattern, apply that localization to predict staging and prognosis, and select the correct management pathway based on stage.