Laryngeal cancer.
1. Definition: Laryngeal cancer is a malignant transformation of the epithelial lining of the larynx. It is anatomically categorized into three regions, which dictate the clinical behavior and spread of the disease:
- Supraglottis: From the epiglottis to the vestibular folds (false cords).
- Glottis: The true vocal cords and the anterior/posterior commissures - most common
- Subglottis: From 1 cm below the vocal cords to the lower border of the cricoid cartilage.
2. Etiopathogenesis
The development of laryngeal SCC is strongly linked to chronic irritation and genetic mutations (gene inactivation).
- Tobacco: The most significant risk factor; the risk is dose-dependent.
- Alcohol: Acts synergistically with tobacco to increase mucosal permeability to carcinogens.
- HPV (Human Papillomavirus): Types 16 and 18 are increasingly recognized, less common here than in the oropharynx.
- Occupational Exposure: Asbestos, mustard gas, and sulfuric acid mists.
- Laryngopharyngeal Reflux (LPR): Chronic acid exposure may act as a promoter.
Pathogenesis
- Epithelial dysplasia → carcinoma in situ → invasive SCC
- Local infiltration, cartilage invasion, early lymphatic spread (supraglottic > glottic)
- Potential perineural and vascular invasion. Heam - late
3. Classification
- Squamous cell carcinoma (95%): Well, moderately, poorly differentiated
- Verrucous carcinoma
- Minor: spindle cell, adenocarcinoma (rare)
TNM Staging - Staging is vital because the larynx has a unique lymphatic distribution.
- T (Tumor):
- T1: Limited to one subsite; normal vocal cord mobility.
- T2: Extension to another subsite (eg, supraglottis to glottis) without fixation.
- T3: Vocal cord fixation or invasion of the paraglottic space.
- T4: Invasion through the thyroid cartilage or into surrounding tissues (trachea, neck skin, esophagus).
- N (Nodes): The supraglottis is rich in lymphatics, while the glottis is nearly devoid of lymphatics.
- M (Metastasis): Usually to the lungs, liver, or bone.
4. Clinical Picture
Symptoms vary significantly by anatomical site:
- Glottic Tumours: Hoarseness, more than 3 weeks. is an early and persistent symptom, Voice fatigue, Throat discomfort, Minimal pain until advanced.
- Supraglottic Tumours: Often "silent" in early stages. Symptoms include Dysphagia, globus sensation (lump in throat), odynophagia (painful swallowing), and referred otalgia (ear pain via the Vagus nerve). It often presents late with a neck mass (early nodal metastasis). Cervical mode
- Subglottic Cancer: Rare; late presentation, usually presents with stridor or dyspnea as the airway narrows.Poorer progn.
- Advanced Signs: Weight loss, Airway obstruction, Cranial nerve involvement (advanced)
5. Paraclinical and Radiological Examinations
- Indirect/Flexible Laryngoscopy: Detects tumor location, size, mobility of vocal cords
- Microlaryngoscopy with Biopsy: Performed under general anaesthesia to Confirms diagnosis.