Makindo Medical Notes

Introduction

Head and neck cancers encompass a diverse group of malignant tumors that develop in or around the throat, larynx, nose, sinuses, and mouth. The majority are squamous cell carcinomas arising from the mucosal lining of these regions. These cancers are often associated with significant morbidity and mortality due to their impact on vital functions such as speech, swallowing, and breathing. Early detection and a multidisciplinary approach to management are crucial for improving patient outcomes.

Head and neck cancers are frequently seen in individuals with a history of tobacco and alcohol use. They are less common in those who do not engage in these risk behaviors.

Epidemiology

• Head and neck cancers represent approximately 4% of all cancers globally:
• Incidence: Around 650,000 new cases worldwide each year.
• Mortality: Approximately 330,000 deaths annually.
• Gender: More common in males than females (about 2:1 ratio).
• Age: Predominantly affects individuals over the age of 50, but incidence is increasing among younger populations due to human papillomavirus (HPV) infection.
• Geographical Variation: Higher incidence in Southeast Asia due to prevalent risk factors like betel nut chewing and tobacco use.

Risk Factors (Etiology)

• Tobacco Use: Smoking cigarettes, cigars, or pipes significantly increases risk. Smokeless tobacco products (chewing tobacco, snuff) are also implicated.
• Alcohol Consumption: High alcohol intake, especially when combined with tobacco use, has a synergistic effect on risk.
• Human Papillomavirus (HPV) Infection:
  • HPV type 16 is strongly associated with oropharyngeal cancers.
  • HPV-positive cancers tend to occur in younger patients and have a better prognosis.
• Epstein-Barr Virus (EBV) Infection: Associated with nasopharyngeal carcinoma, particularly in certain ethnic groups.
• Age: Risk increases with age, most cases occurring in people over 50.
• Gender: Male gender is a risk factor, possibly due to higher rates of tobacco and alcohol use.
• Dietary Factors: Poor nutrition, low intake of fruits and vegetables.
• Occupational Exposures: Exposure to wood dust, asbestos, certain chemicals, and industrial toxins.
• Radiation Exposure: Prior therapeutic radiation to the head and neck region.
• Genetic Predisposition: Familial syndromes such as Fanconi anemia and dyskeratosis congenita.
• Leukoplakia and Erythroplakia: Premalignant lesions that can progress to squamous cell carcinoma.
• Betel Nut Chewing: Common in some Asian populations, increases risk of oral cancers.

Pathological type is essential for diagnosis and treatment planning:

• Histological Types:
  • Squamous Cell Carcinoma (SCC): Accounts for more than 90% of head and neck cancers. Originates from the mucosal epithelium.
  • Adenocarcinomas: Arise from glandular tissues like salivary glands.
  • Lymphomas: Cancers of lymphoid tissue in the head and neck region.
  • Sarcomas: Originating from connective tissues.
  • Melanomas: Malignant tumors of melanocytes in mucosal surfaces.
• Patterns of Spread:
  • Local Invasion: Direct extension into adjacent tissues.
  • Lymphatic Spread: Commonly metastasize to regional cervical lymph nodes.
  • Perineural Invasion: Cancer cells spread along nerve sheaths, potentially reaching the skull base.
  • Hematogenous Spread: Less common; distant metastases to lungs, liver, bones.

Anatomical Sites Affected

• Oral Cavity: Lips, anterior two-thirds of the tongue, gums, floor of the mouth, hard palate.
• Pharynx:
  • Nasopharynx: Upper part behind the nose.
  • Oropharynx: Middle part including the base of the tongue, tonsils, soft palate.
  • Hypopharynx: Lower part connecting to the esophagus.
• Larynx: Voice box, includes supraglottis, glottis, and subglottis.
• Nasal Cavity and Paranasal Sinuses: Air-filled spaces around the nose.
• Salivary Glands: Parotid, submandibular, and sublingual glands.
• Ear: External auditory canal and middle ear.

Clinical Presentation depends on the tumor location and extent

• Neck Mass: Enlarged cervical lymph nodes, often the first sign.
• Persistent Sore Throat or Hoarseness: Especially with laryngeal involvement.
• Dysphagia: Difficulty swallowing due to oropharyngeal or hypopharyngeal tumors.
• Odynophagia: Painful swallowing.
• Non-Healing Ulcers: Ulcer or sore in the mouth that does not heal.
• Leukoplakia or Erythroplakia: White or red patches in the oral cavity.
• Nasal Obstruction or Epistaxis: Nasal cavity or sinus tumors may cause nasal blockage or bleeding.
• Otalgia: Referred ear pain without ear pathology, often due to glossopharyngeal nerve involvement.
• Trismus: Difficulty opening the mouth, suggestive of muscle or nerve involvement.
• Weight Loss: Due to difficulty eating and systemic effects of cancer.
• Breathing Difficulties: Airway obstruction in advanced laryngeal tumors.
• Facial Numbness or Paralysis: Indicates perineural invasion.

Diagnosis and Investigations

• History and Physical Examination:
  • Detailed head and neck examination, including oral cavity inspection.
  • Assessment of lymph nodes and cranial nerve function.
• Laboratory Tests:
  • Complete Blood Count (CBC): Assess for anemia or infection.
  • Renal and Liver Function Tests: Baseline before treatment.
  • Coagulation Profile: Especially before biopsy or surgery.
• Imaging Studies:
  • Contrast-Enhanced CT Scan: Evaluates tumor extent and lymph node involvement.
  • MRI: Superior for soft tissue detail and perineural spread assessment.
  • Positron Emission Tomography (PET) Scan: Detects distant metastases and synchronous tumors.
  • Chest Imaging: Chest X-ray or CT scan to rule out pulmonary metastasis.
• Endoscopic Examination:
  • Flexible nasoendoscopy to visualize nasal passages, pharynx, and larynx.
  • Panendoscopy under general anesthesia for comprehensive assessment and biopsy.
• Biopsy:
  • Fine-Needle Aspiration Cytology (FNAC): Of lymph nodes or palpable masses.
  • Incisional or Excisional Biopsy: For tissue diagnosis.
• Histopathological Examination:
  • Determines tumor type, grade, and margins.
  • HPV and EBV testing where appropriate.

Staging

Staging is based on the TNM (Tumor, Node, Metastasis) system:

• T (Tumor): Size and extent of the primary tumor.
• N (Node): Regional lymph node involvement.
• M (Metastasis): Presence of distant metastases.

Accurate staging guides treatment planning and prognosis estimation.

Management

Treatment requires a multidisciplinary approach involving otolaryngologists, head and neck surgeons, medical oncologists, radiation oncologists, dental specialists, nutritionists, speech therapists, and supportive care teams.

General Principles

• Early Detection: Improves the likelihood of successful treatment.
• Preservation of Function: Aim to maintain speech, swallowing, and appearance.
• Individualized Treatment: Based on tumor location, stage, patient health, and preferences.
• Rehabilitation and Support: Nutritional support, speech therapy, psychosocial support.

Treatment Modalities

Surgery

• Local Excision: For small, localized tumors.
• Partial or Total Resection: Depending on tumor size and location (e.g., partial glossectomy, laryngectomy).
• Neck Dissection: Removal of regional lymph nodes to control metastatic spread.
• Reconstructive Surgery:
  • Use of local, regional, or free flaps to restore form and function.
  • Microvascular free tissue transfer techniques have improved outcomes.

Radiation Therapy

• External Beam Radiation: Commonly used, either alone or postoperatively.
• Intensity-Modulated Radiation Therapy (IMRT): Allows precise targeting, sparing normal tissues.
• Brachytherapy: Internal radiation for selected cases.
• Complications: Mucositis, xerostomia (dry mouth), dysphagia, skin changes.

Chemotherapy

• Neoadjuvant Chemotherapy: Given before surgery or radiation to shrink tumors.
• Concurrent Chemoradiotherapy: Enhances the effects of radiation therapy.
• Palliative Chemotherapy: For advanced or metastatic disease to alleviate symptoms.
• Common Agents: Cisplatin, fluorouracil (5-FU), docetaxel.

Targeted Therapy and Immunotherapy

• Targeted Agents:
  • EGFR Inhibitors: Cetuximab used in combination with radiation or chemotherapy.
• Immunotherapy:
  • Checkpoint Inhibitors: Pembrolizumab and nivolumab for recurrent or metastatic disease.

Supportive Care

• Nutritional Support:
  • Dietitian involvement to manage dysphagia and maintain weight.
  • Percutaneous endoscopic gastrostomy (PEG) tube placement if necessary.
• Speech and Swallowing Therapy: Rehabilitation to improve function post-treatment.
• Pain Management: Adequate analgesia for symptom control.
• Psychosocial Support: Counseling and support groups for patients and families.
• Smoking and Alcohol Cessation: Critical to reduce risk of second primary tumors and improve treatment outcomes.

Follow-Up and Surveillance

• Regular follow-up appointments for early detection of recurrences or second primary tumors.
• Monitoring includes physical examinations, imaging studies, and endoscopic evaluations.
• Management of long-term treatment effects, such as dry mouth, dental issues, and hypothyroidism.

Prognosis

Prognosis depends on several factors:

• Stage at Diagnosis: Early-stage cancers have better survival rates.
• Tumor Location: Some sites have worse prognosis (e.g., hypopharyngeal cancers).
• HPV Status: HPV-positive oropharyngeal cancers have improved outcomes.
• Patient Factors: Age, comorbidities, nutritional status.
• Treatment Response: Complete response to therapy indicates better prognosis.

Overall 5-year survival rates range from 40% to 60%, varying by site and stage.

Prevention

• Tobacco and Alcohol Cessation: Reduces risk significantly.
• HPV Vaccination: Protects against HPV strains associated with oropharyngeal cancers.
• Regular Dental and Medical Check-Ups: Early detection of precancerous lesions.
• Occupational Safety: Use of protective equipment to reduce exposure to carcinogens.
• Healthy Diet: Increased intake of fruits and vegetables.

Conclusion

Head and neck cancers pose significant challenges due to their impact on essential functions and aesthetic considerations. A multidisciplinary approach is essential for optimal management, focusing on eradication of the disease while preserving quality of life. Advances in surgical techniques, radiation therapy, and systemic treatments have improved outcomes. Early detection, prevention strategies, and patient education remain critical components in reducing the burden of these cancers.

References

• National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers. Version 1.2021.
• Argiris A, Karamouzis MV, Raben D, Ferris RL. Head and neck cancer. Lancet. 2008;371(9625):1695-1709.
• Chaturvedi AK, Engels EA, Pfeiffer RM, et al. Human papillomavirus and rising oropharyngeal cancer incidence in the United States. J Clin Oncol. 2011;29(32):4294-4301.
• Marur S, Forastiere AA. Head and neck squamous cell carcinoma: update on epidemiology, diagnosis, and treatment. Mayo Clin Proc. 2016;91(3):386-396.
• Colevas AD, Yom SS, Pfister DG, et al. NCCN Guidelines Insights: Head and Neck Cancers, Version 1.2018. J Natl Compr Canc Netw. 2018;16(5):479-490.
• Schlecht NF, Brandwein-Gensler M, Nuovo GJ, et al. A comparison of clinically utilized human papillomavirus detection methods in head and neck cancer. Mod Pathol. 2011;24(10):1295-1305.