What is the procedure for cryotherapy in a patient with local recurrence of conjunctival melanoma?

Cryotherapy Procedure for Conjunctival Melanoma Local Recurrence

Cryotherapy for conjunctival melanoma recurrence should be performed using a double freeze-thaw technique with liquid nitrogen applied to the tumor margins after complete surgical excision, using a "no-touch" technique to avoid tumor cell seeding. 1, 2

Surgical Excision First

• Complete surgical excision with negative margins is the mandatory first step before any adjuvant cryotherapy is applied 3, 2
• The "no-touch" method must be employed during excision, avoiding any direct manipulation of the tumor to prevent seeding tumor cells into new areas 3
• Excision should include a margin of normal-appearing conjunctiva around the visible tumor 2

Cryotherapy Application Technique

• Liquid nitrogen is the cryogen of choice for treating conjunctival melanoma 2, 4
• Apply cryotherapy to the surgical margins immediately after excision, targeting the conjunctival edges and any areas of suspected microscopic disease 2, 4
• Use a double freeze-thaw cycle: freeze the tissue until an ice ball forms, allow complete thawing, then refreeze 2
• The freeze should extend approximately 2-3 mm beyond the visible tumor margins to address microscopic extension 2

Specific Anatomical Considerations

• For limbal lesions, cryotherapy should be applied to the limbal area and adjacent sclera 2
• For forniceal, palpebral, or caruncular involvement (which carry worse prognosis), more extensive cryotherapy may be needed, though these locations have higher metastatic rates regardless of treatment 2
• Avoid excessive cryotherapy near the lacrimal drainage system to prevent obstruction 3

Combined Treatment Approach

• Cryotherapy alone is insufficient; it must be combined with complete surgical excision to minimize the high local recurrence rate seen with excision alone 1, 3, 4
• Some centers combine surgery and cryotherapy with additional radiotherapy (proton-beam or cobalt plaque) for extensive or high-risk recurrent tumors 1
• Topical mitomycin C (MMC) chemotherapy may be added as another adjuvant modality 3

Expected Outcomes and Monitoring

• Even with combined surgery and cryotherapy, unifocal melanomas have approximately a 90% success rate after one or two treatments 2
• Multinodular or multicentric melanomas have a 45% metastasis rate despite multiple therapies, particularly when involving non-limbal locations 2
• Tumors greater than 2 mm thickness or involving fornix/caruncle have significantly worse prognosis 2, 4
• Indefinite follow-up with photodocumentation is mandatory due to high recurrence rates 3

Critical Pitfalls to Avoid

• Never perform cryotherapy without complete surgical excision first—cryotherapy is an adjuvant, not primary treatment 2, 4
• Avoid direct tumor manipulation during excision, as this increases risk of local seeding 3
• Do not underestimate the extent of disease; PAM sine pigmento (microscopically present but clinically invisible) is associated with metastasis 2
• Recognize that delayed treatment significantly worsens prognosis—refer to an ophthalmo-oncological center promptly 3