What is the treatment for adenoid cystic carcinoma (ACC) of the nose?

Treatment of Adenoid Cystic Carcinoma of the Nose

The optimal treatment for adenoid cystic carcinoma (ACC) of the nose is surgical resection with clear margins followed by postoperative radiation therapy to maximize disease control and survival outcomes. 1, 2

Clinical Characteristics and Presentation

• ACC is the second most common malignancy occurring in the sinonasal tract, with the maxillary sinus (47%) and nasal cavity (30%) being the most common primary sites 3
• Approximately 70-77% of patients present with advanced disease (T3/T4) at the time of diagnosis 1, 3
• The cribriform histologic subtype is most common (61%) in sinonasal ACC 1
• Lymph node metastasis is rare in sinonasal ACC, with rates as low as 2-4% 3, 4
• Distant metastasis is more common, occurring in 25-38% of patients 1, 3

Treatment Approach

Primary Treatment

• Combined modality treatment with radical surgery followed by postoperative radiation therapy offers the best chance for disease control and survival 1, 2, 3
• Complete surgical resection with negative margins (R0 resection) is crucial for long-term survival 5
• For locally advanced disease, it may be necessary to resect adjacent structures to achieve negative margins 5

Surgical Considerations

• The goal of surgery should be complete tumor removal with clear margins 5
• Perineural invasion is common in ACC and significantly impacts local control 6
• If facial nerve branches are found to be encased or grossly involved by the tumor, they should be resected 5
• Elective neck dissection is generally not recommended for clinically negative necks due to the low rate of lymphatic metastasis 4

Radiation Therapy

• Postoperative radiation therapy should be offered to all patients with resected ACC 5
• Radiation therapy has been shown to reduce local recurrence rates 1
• The high-dose target should cover the surgical bed and appropriate nodal levels 5
• In cases with perineural invasion, the associated nerve(s) may be covered with an elective or intermediate dose to the skull base 5

Follow-up and Surveillance

• Regular follow-up is essential due to the high risk of local recurrence and distant metastasis 5, 1
• Follow-up should include clinical examination, endoscopic evaluation, and imaging studies 5
• MRI is often used to evaluate the response to treatment, especially for advanced tumors 5
• Chest CT should be performed regularly to monitor for lung metastases, which are common in ACC 5
• Follow-up should continue for at least 10 years due to the risk of late recurrence 5

Prognosis and Outcomes

• 5-year overall survival rates range from 54-86% 1, 3, 6
• Local recurrence rates are approximately 30% despite aggressive treatment 1, 3
• Distant metastasis rates range from 25-38% 1, 3
• Presence of distant metastasis significantly decreases 5-year survival (17% vs. 58% for local recurrence) 1
• Factors associated with worse prognosis include advanced stage, perineural invasion, positive margins, and cranial nerve involvement 6, 4

Management of Recurrent or Metastatic Disease

• For small local recurrences, treatment options include surgical resection, stereotactic radiation therapy, or a combination of surgery and radiation therapy 5
• Regional recurrence should be managed by radical neck dissection if resectable 5
• For patients with limited metastatic disease (≤5 metastases), particularly in ACC with indolent biology, local ablative treatments such as surgery (metastasectomy) or stereotactic body radiation therapy may be offered 5
• In patients with metastatic disease, palliative chemotherapy with platinum-based regimens may be considered 5

Common Pitfalls and Caveats

• Underestimating the extent of disease due to perineural spread, which may not be apparent on imaging 5
• Inadequate surgical margins leading to increased risk of local recurrence 6
• Insufficient follow-up duration, as ACC can recur many years after initial treatment 5
• Focusing solely on local control while overlooking the high risk of distant metastasis 1, 3
• Assuming complete clinical response to treatment indicates cure, as ACC has a propensity for late recurrence 5