What is the optimal management for a T4c N1 M0 lacrimal gland adenoid cystic carcinoma?

Management of T4c N1 M0 Lacrimal Gland Adenoid Cystic Carcinoma

For T4c N1 M0 lacrimal gland adenoid cystic carcinoma, perform surgical resection (likely requiring orbital exenteration given T4c status) followed by postoperative radiotherapy with ipsilateral neck dissection of involved and at-risk nodal levels.

Surgical Approach

The T4c designation indicates orbital invasion beyond the periorbita, which typically necessitates aggressive surgical resection. While the evidence shows a trend toward globe-sparing surgery in earlier stages 1, T4c disease with nodal involvement requires more extensive resection to achieve adequate margins.

For the N1 neck disease, perform ipsilateral neck dissection of involved and at-risk levels, potentially extending to adjacent levels up to levels 1-5 2. This recommendation comes directly from ASCO guidelines for salivary gland malignancies, which apply to adenoid cystic carcinoma management. The guideline specifically addresses cN1 neck management with moderate strength recommendation.

Key Surgical Considerations:

• T4c tumors have invaded beyond the orbital periorbita, making complete resection challenging
• Adenoid cystic carcinoma characteristically demonstrates perineural invasion requiring wide margins
• Globe preservation is unlikely feasible at this advanced stage, though recent literature shows 64% overall eye preservation rates in less advanced cases 3

Adjuvant Radiotherapy

Postoperative radiotherapy is mandatory for all adenoid cystic carcinoma cases 2. This is a strong recommendation (category 1) from ASCO guidelines with intermediate evidence quality. Your case has multiple high-risk features mandating RT:

• Adenoid cystic histology (automatic indication)
• T4 tumor (high-risk feature)
• Lymph node metastases (N1 disease)
• Likely perineural invasion (characteristic of ACC)

Radiotherapy Technical Details:

Use conventionally-fractionated radiotherapy rather than stereotactic body radiotherapy (SBRT). Recent evidence from 2025 shows SBRT resulted in significantly worse local control (20% vs 72% at 10 years) and higher severe late toxicity (80% vs 17%) compared to conventional fractionation 3.

The high-dose target should cover:

• The surgical bed and orbital region
• Appropriate nodal levels (ipsilateral neck levels 1-5 given N1 disease)
• Perineural pathways to the skull base given the characteristic perineural invasion of ACC 2

Particle therapy (proton or carbon-ion) may be considered but shows no clear superiority over photon therapy 2. Recent data from 2026 showed no significant differences in 5-year outcomes between proton/carbon-ion versus photon radiotherapy 1.

Expected Outcomes and Prognosis

Based on the most recent high-quality evidence 1:

• Surgery plus radiotherapy improves 5-year recurrence-free survival (63.4% vs 31.1% for surgery alone, p=0.014)
• 5-year progression-free survival improves (56.8% vs 31.1%, p=0.036)
• However, overall survival shows no significant improvement (79.7% vs 85.6%, p=0.98)
• Distant metastasis-free survival remains unchanged (67.3% vs 70.1%, p=0.70)

This indicates that while local control improves with multimodal therapy, the ultimate prognosis is limited by distant metastatic disease, which is common in ACC.

Critical Pitfalls to Avoid

1. Do not use SBRT/hypofractionated radiotherapy - The 2025 French study definitively shows worse outcomes with this approach 3

2. Do not omit neck dissection - Despite ACC traditionally having low rates of nodal metastases, your patient has clinical N1 disease requiring surgical management 2

3. Do not limit radiation fields - Must include perineural pathways to skull base given ACC's propensity for perineural spread 2

4. Do not consider chemotherapy as primary adjuvant treatment - While neoadjuvant intra-arterial chemotherapy shows promise in research settings 4, the standard remains surgery plus radiotherapy. Chemotherapy has no established role in the adjuvant setting for this disease.

Long-term Surveillance

Expect high rates of late complications if any orbital structures are preserved:

• Dry eye disease (100% in eye-sparing cases)
• Cataract progression (45.7%)
• Severe vision loss occurs in 40% of preserved eyes 1

Monitor closely for distant metastases to lungs, bone, and liver, as these remain the primary cause of mortality despite excellent local control 5, 6.