Radiation Oncology/Head & Neck/Sinonasal/Ethmoid sinuses
|
Ethmoid cancer
Risk factors
edit- Occupational
- Sawdust, cement dust - ethmoid adenocarcinoma
- Exposure to thoratrast, nickel, cadmium, formaldehyde
- Pollution
- Smoking
- HPV (SCC)
- ?chronic sinusitis
Pathology
edit- SCC most common
- Mucoepidermoid
- Adenoid cystic
- Adenocarcinoma
- Rare:
- Olfactory neuroblastomas (esthesioneuroblastoma)
- Angiosarcoma
- Rhabdomyosarcoma
- Lymphoma
Natural history
edit- Usually well differentiated, slow growing
- Present due to local invasion beyond sinus although can sometimes present due to sinusitis or nasal obstruction
- Tumours commonly invade through bone - through cribriform plate to anterior cranial fossa, or lamina papyracea to orbit
Route of spread
edit- Primarily through local invasion; nodal metastases are uncommon (< 20%, even lower for adenoid cystic)
- Nodal involvement is more common when there is extension into surrounding tissues
- Sinuses themselves are lymphatic poor
- First echelon lymph nodes are retropharyngeal
Presentation
edit- Facial or nasal pain
- Epistaxis
- Sinus obstruction
- Trismus (pterygoid involvement)
- Ocular symptoms: diplopia, visual disturbance, proptosis
- Neural involvement eg trigeminal neuralgia
Staging
editSee Staging
Outcomes
edit- Local control 50-60%
- Overall survival 30-50% at 5 years
Management
edit- Most evidence is via retrospective single institution reports
- Options:
- Surgery (eg craniofacial resection, orbital exenteration)
- Often difficult as locally advanced by the time of presentation
- May include orbital exenteration if there is orbital invasion
- Radiotherapy
- Unclear whether preop or postop RT is better
- Preop chemoRT may improve resectability
- Adjuvant treatment does appear to increase local control although there exists no randomised data to confirm this
- Radiotherapy as definitive management is most appropriate
- Difficult resection anatomically
- Dose 70Gy definitive, with chemotherapy for advanced lesions
- Comprehensive nodal irradiation (retropharyngeal nodes) only if node positive or extrasinus involvement (skin, muscle)
- Dose limiting structures
- Eye, optic chiasm
- Brain
- Technique
- Ant and wedged laterals (posterior to eye)
- Treat neck nodes prophylactically if there is skin/muscle involvement otherwise target volume is antrum alone
- Unclear whether preop or postop RT is better
- Surgery (eg craniofacial resection, orbital exenteration)