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Squamous Cell Carcinoma (SCC) of the Maxillary Sinus

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1. INTRODUCTION & EPIDEMIOLOGY

• Scott-Brown's Otorhinolaryngology, Ch. 7

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2. AETIOLOGY / RISK FACTORS

• Occupational exposure accounts for ~40% of reported sinonasal malignancies.
• Chronic sinusitis does NOT predispose to cancer.
• Scott-Brown's, p.117

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3. SURGICAL ANATOMY (Relevant to Spread)

• Anterior wall - thin; tumours erode through to the cheek/skin
• Posterior wall - overlies the pterygopalatine and infratemporal fossa
• Medial wall - separates from the nasal cavity; contains the ostium; close to the nasolacrimal duct
• Superior wall (roof) - floor of the orbit; contains the infraorbital nerve in the infraorbital canal
• Inferior wall (floor) - close to the roots of upper molar/premolar teeth
• Superolateral wall - forms the orbital floor laterally

• Anterior pathway: to facial, parotid, and submandibular nodes → upper deep cervical chain
• Posterior pathway: retropharyngeal nodes → upper deep cervical chain

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4. CLASSIFICATION OF MAXILLARY SINUS TUMOURS

4a. Histological Classification

• Approximately 85% are well-differentiated
• Papillary, exophytic, fungating, friable, and keratinizing patterns are recognized
• Macroscopically may be polypoid or fungating
• Transformation from Schneiderian papilloma is a recognized pathway

4b. Ohngren's Classification (Prognostic)

Tumours antero-inferior to this line have better treatment outcomes. - KJ Lee, p.597

4c. Anatomical Infrastructure vs Superstructure Division

• Infrastructure lesions - involve the floor of the antrum, alveolus, hard palate
• Superstructure lesions - involve the roof of the antrum (orbital floor) and above

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5. PATTERNS OF TUMOUR SPREAD

Local Spread - Maxillary Sinus

Regional (Lymph Node) Spread

• Lymphatic spread becomes apparent in 25-35% at some point during disease
• Only ~10% present with nodal disease (marker of locally advanced disease)
• Most commonly: submandibular and jugulodigastric nodes
• Bilateral involvement possible when tumour involves midline structures

Distant Metastases

• Uncommon at presentation; develop in ~10% of SCC (vs 20% of adenocarcinomas)
• Sites: bone, brain, liver, lung, skin
• Almost always associated with local recurrence
• Scott-Brown's, pp.118-119

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6. CLINICAL FEATURES

6a. Early (Non-specific) Symptoms

• Unilateral nasal obstruction
• Unilateral blood-stained nasal discharge (epistaxis)
• Facial pain/pressure

6b. Symptoms by Direction of Spread

6c. Key Clinical Sign

• Scott-Brown's, pp.124-125

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7. INVESTIGATIONS

7a. Endoscopy

• Rigid nasal endoscopy is mandatory in any suspected sinonasal malignancy
• May show ulcerative growth, polypoid reaction, or friable mass
• Some tumours produce a polypoid reaction in overlying mucosa - casual outpatient biopsy may be non-diagnostic

7b. Imaging

• Required for ALL patients
• Both axial and coronal views are necessary
• Demonstrates bone erosion, extent of antral destruction
• Better for skull base involvement and bone integrity
• May be compromised by dental amalgam artefact

• Gadolinium-enhanced MRI is superior for:
  • Distinguishing tumour from retained secretions (T2 and diffusion-weighted sequences)
  • Perineural spread (most malignant tumours enhance diffusely vs rim enhancement of secretions)
  • Intracranial and dural infiltration
  • Orbital invasion
  • Extent in pterygopalatine fossa and infratemporal fossa
• CT + MRI together are complementary and both are commonly required

• To exclude pulmonary metastases
• Mandatory before planning curative treatment

• Not usually needed for staging the primary
• Useful for excluding distant disease (e.g., melanoma)
• Helpful if concern exists that sinus disease is metastatic

7c. Biopsy

• Tissue diagnosis is mandatory before any treatment
• Sinus tumours can be excessively vascular - outpatient biopsy must have facilities to arrest haemorrhage
• Biopsy under general anaesthesia preferred - reduces non-diagnostic rate, allows sampling from within the sinus
• Caldwell-Luc approach should be avoided if it might seed tumour or compromise resection

7d. Examination Under Anaesthesia (EUA)

• Thorough examination including palpation of the palate, alveolus, and posterior pharynx

7e. MDT Discussion

• All cases to be discussed in a multidisciplinary team (MDT) forum before treatment planning, including surgical oncology, radiation oncology, reconstructive surgery, prosthetics.
• Scott-Brown's, pp.124-126

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8. TNM STAGING (AJCC)

Maxillary Sinus T Staging

N (Nodal) and M (Distant) Staging

• Same as routine head and neck SCC staging
• N0: no regional node metastasis
• N1: single ipsilateral node ≤3cm
• N2: larger/multiple nodes
• M1: distant metastases present

Staging Matrix (Overall Stage)

• KJ Lee's Essential Otolaryngology, pp.596-597; Scott-Brown's, p.119

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9. MANAGEMENT

9a. General Principles

• Patients with T1 tumours may be cured with surgery alone
• The majority require combination (multimodality) therapy
• Surgery + radiotherapy ± chemotherapy is the standard curative approach
• IMRT (Intensity Modulated Radiotherapy) is the preferred radiotherapy technique
• Cases should be discussed at MDT before treatment

9b. Surgery

1. Lateral rhinotomy (Michaux/Moure) - excellent exposure of nasal cavity and medial maxilla; cosmetically acceptable incision in the lateral nasal crease
2. Weber-Fergusson incision - for total maxillectomy; combines lateral rhinotomy with a lip-splitting incision for wider exposure
3. Midfacial degloving - avoids facial scars; useful for bilateral access

• Elective levels I-III neck dissection considered for T2 or greater lesions
• Cervical metastasis demonstrated in 35% of hard palate/maxillary alveolar carcinomas
• Facial lymph nodes should be considered during neck dissection for maxillary tumours

9c. Radiotherapy

• Post-operative radiotherapy (PORT) should start within 6 weeks of surgery
• Dose: 60-65 Gy over 30 fractions (IMRT technique)
• PORT indications: T3 or greater disease, positive margins, perineural or perivascular invasion, multiple cervical nodes (especially with extracapsular spread)
• Elective neck irradiation considered for locally advanced (T3-T4) disease due to 23% risk of locoregional recurrence

9d. Chemotherapy

• Used in multimodality regimens for advanced or metastatic disease, or SCC/SNUC
• Cisplatin-based protocols most commonly used
• Concurrent chemoradiotherapy for non-resectable cases
• Palliative chemotherapy for unresectable/metastatic disease

9e. Combined Modality Therapy

• For SCC and SNUC: surgery + post-operative radiotherapy ± chemotherapy has the best outcomes
• If operable: surgery first, then post-operative radiotherapy with concurrent chemotherapy where indicated
• IMRT with advanced planning and concurrent chemotherapy provides significant value

9f. Reconstruction

• Small defects: buccal fat pad, temporalis flap, facial artery musculomucosal flap
• Large defects: free tissue transfer (soft tissue or composite flaps)
• Palatal resection: obturator prosthesis (fitted with teeth to restore speech and deglutition) OR composite free flap
• Orbital resections: titanium implants for facial prostheses
• Multidisciplinary prosthetic rehabilitation is an essential component
• Scott-Brown's, pp.126-130

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10. PROGNOSIS

• 5-year absolute survival for hard palate carcinoma: 57%; alveolar carcinoma: 49%
• Locoregional control of maxillary tumours after initial therapy: ~40-45%
• Over 90% of recurrences occur within the first 2 years
• Distant metastases in ~10% of SCC (vs 20% adenocarcinoma)
• Scott-Brown's, p.131; KJ Lee, p.597

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SUMMARY TABLE