What is the treatment approach for a patient diagnosed with ocular squamous cell carcinoma?

Treatment of Ocular Squamous Cell Carcinoma

For ocular surface squamous neoplasia (OSSN), local excision with cryotherapy to the surgical edges performed by an experienced specialist is the primary treatment, with topical chemotherapeutic agents (interferon, mitomycin-C, or 5-fluorouracil) serving as effective adjunctive or standalone therapy. 1, 2

Primary Treatment Strategy

Surgical excision remains the cornerstone of management and must be performed by a surgeon experienced in treating ocular tumors. 1, 2 The excision should assess:

• Presence or absence of invasion into underlying tissues 2
• Tumor margins (minimum 4mm for well-defined lesions <2cm, 6mm or more for high-risk features) 1
• Degree of differentiation 2
• Vascular, lymphatic, perineural, intraocular, or intraorbital invasion 2

Cryotherapy applied to the surgical edges is essential to eliminate residual tumor cells that may remain after excision. 1, 2

Topical Chemotherapy Options

The optimal treatment approach remains debated, but topical chemotherapeutics alone may completely resolve the malignancy in select cases. 1 Available agents include:

• Interferon alfa-2b 1, 3
• Mitomycin-C 1, 3
• 5-Fluorouracil (5-FU) 1, 3

These can be used as adjunctive therapy post-excision or as primary treatment for patients unsuitable for surgery. 1, 2

Advanced Disease Management

For regional lymph node metastases, treatment escalates to: 2

• Surgical resection with lymph node dissection
• Adjuvant radiation therapy with or without concurrent systemic therapy
• Combination chemoradiation for inoperable lymph node disease

For distant metastatic disease, palliative options include: 2

• Weekly methotrexate
• Combination chemotherapy regimens
• Cetuximab added to platinum-based chemotherapy

High-Risk Features Requiring Aggressive Management

Identify these factors that predict aggressive behavior: 2

• Tumor size >2cm
• Depth >4mm
• Poor differentiation
• Perineural or vascular invasion 4
• Immunosuppressed patient status

Perineural invasion warrants particular vigilance as it associates with poorer prognosis. 4

Radiation Therapy Considerations

Primary radiotherapy provides excellent locoregional control (88% local control at 5 years) with reasonable complication rates and should be considered an alternative to surgery in selected patients. 5 Postoperative radiation is indicated for: 1

• Perineural invasion
• Incomplete resection with positive surgical margins
• High-risk features on pathology

Monitoring and Follow-up

Anterior segment optical coherence tomography facilitates both diagnosis and follow-up monitoring for treatment response. 1, 2 Regular clinical examination and imaging are essential for early detection of recurrence, as recurrence rates are higher for ocular malignancies than cutaneous counterparts. 3

Critical Pitfalls to Avoid

• Do not attempt narrow excision margins (<4mm) for well-defined lesions, as this increases residual tumor risk 1
• Do not overlook the anophthalmic socket in enucleated patients, as OSSN can develop decades post-enucleation 6
• Do not delay treatment, as management should be performed by an experienced specialist given the complexity and debate surrounding optimal approaches 1, 2
• Do not assume clinical margins predict microscopic extent accurately, particularly for ill-defined tumors 1