Treatment of Adenoid Cystic Carcinoma of the Nasal Septum
Complete surgical resection with negative margins followed by postoperative radiation therapy is the recommended treatment for adenoid cystic carcinoma of the nasal septum to maximize survival and reduce local recurrence rates. 1
Surgical Management
- Complete surgical resection with negative margins is crucial for long-term survival and may require resection of adjacent structures to achieve clear margins 1
- The surgical approach should be determined based on tumor location, extent, and involvement of surrounding structures, potentially requiring combined approaches (endoscopic, open, or craniofacial) to achieve complete resection 2
- If facial nerve branches or other major named nerves are found to be encased or grossly involved by the tumor, they should be resected to achieve negative margins 1
- Achieving negative margins is particularly important as positive margins significantly increase the risk of local recurrence (18% vs 5% for negative margins) 3
Radiation Therapy
- Postoperative radiation therapy should be offered to all patients with resected adenoid cystic carcinoma, even with negative margins, due to the high risk of microscopic residual disease 1, 3
- A total dose of 60 Gy to the tumor bed is recommended, supplemented to 66 Gy for patients with positive margins 3
- Intensity-modulated radiation therapy may offer improved local tumor control while reducing toxicity to surrounding critical structures 1, 4
- Field size and dose adequacy are critical factors in preventing local recurrence, with fields exceeding 8×8 cm and doses exceeding 45 Gy showing significantly better local control 5
Treatment Considerations for Advanced Disease
- For tumors with skull base invasion or extensive local spread, a multidisciplinary approach combining anterior cranial surgery, endoscopic intranasal surgery, and/or transpalatal surgery may be required 2
- Perineural invasion, particularly of named nerves, is an adverse prognostic factor and should be addressed in treatment planning 3
- Despite effective local therapy with surgery and radiation, approximately one-third of patients develop distant metastases, most commonly to the lungs 3, 6
Follow-up and Surveillance
- Regular follow-up is essential due to the high risk of local recurrence and distant metastasis 1
- Follow-up should include clinical examination, endoscopic evaluation, and imaging studies (MRI for local recurrence, CT chest for lung metastases) 1
- Long-term follow-up for at least 10 years is necessary due to the risk of late recurrence 1, 6
Management of Recurrent Disease
- For small local recurrences, treatment options include surgical resection, stereotactic radiation therapy, or a combination of surgery and radiation therapy 1
- Regional recurrence should be managed by radical neck dissection if resectable 1
- For patients with limited metastatic disease, local ablative treatments may be considered 1
Common Pitfalls and Caveats
- Underestimating the extent of disease due to perineural spread is a common pitfall 1
- Insufficient follow-up duration can lead to overlooking late recurrences, as local failures can occur even 5+ years after treatment 3, 6
- Despite excellent local control with combined surgery and radiation (70-86% at 5 years), distant metastases remain a significant challenge, occurring in 25-38% of patients 7, 6
- The 5-year overall survival rate for sinonasal adenoid cystic carcinoma ranges from 62-86%, but this drops significantly to 17% after development of distant metastasis 6