What is the indication for Crylar (cryotherapy)?

Indications for Cryotherapy (Crylar)

Cryotherapy is primarily indicated for the treatment of actinic keratoses (AKs), with a strength of recommendation A and quality of evidence I. 1 It is also effective for treating certain types of skin lesions including superficial basal cell carcinomas and Bowen's disease.

Primary Indications for Cryotherapy

Actinic Keratoses (AKs)

• First-line treatment for individual AK lesions
• Complete response rates of 75-85% for AKs 1
• Particularly effective for thick lesions (69% complete response vs 52% for PDT) 1
• Duration of freeze affects clearance rates:
  • <5 seconds: 39% cure
  • 5-20 seconds: 69% cure

  • 20 seconds: 83% cure 1, 2

Other Dermatological Indications

• Superficial basal cell carcinomas (87% clearance rate) 1
• Bowen's disease (82% clearance rate) 1
• Field treatment of multiple AKs (referred to as "cryopeeling") 1

Treatment Protocol

For Actinic Keratoses:

1. Apply liquid nitrogen with cryospray or cotton-tipped applicator
2. For optimal results, use a double freeze-thaw cycle 1
3. Freeze for 5-20 seconds until 1-2mm of circumferential skin appears frozen
4. Allow to thaw for 20-60 seconds
5. Repeat freeze step
6. Repeat entire process at 3-week intervals until healing occurs 1

For Basal Cell Carcinomas:

• Prior de-bulking curettage may improve efficacy for nodular BCC (92% vs 0% for PDT or curettage alone) 1
• Consider double PDT treatments for nodular lesions 1

Advantages and Limitations

Advantages:

• Long-established treatment with proven efficacy 1
• Flexible therapy for various skin lesions 1
• Can be used in primary and secondary care settings 1
• 77% of patients need only one treatment for complete response 1

Limitations:

• Side effects include soreness, blistering, pigmentary changes, and scarring 1, 2
• Inferior cosmetic outcomes compared to photodynamic therapy 1
• Not recommended for:
  • Fingers, nose, ears, eyelids, or near lips 1, 2
  • Patients with evidence of potential dissemination 1
  • Lower leg lesions (may heal poorly) 2

Patient Considerations

Risk of Adverse Effects:

• Higher risk of pigmentary changes in darker skin types 2
• Immediate reactions include vesicle formation, erythema, swelling, and burning pain 1
• Both hypo- and hyperpigmentation can occur and may persist for 6-12 months 1

Patient Selection:

• Best for smaller, recent-onset, uncomplicated lesions 1
• Can be used during pregnancy and breastfeeding 1
• Consider alternative treatments for cosmetically sensitive areas 2

Clinical Pearls

• The success of cryotherapy is highly dependent on the skill of the operator and complete, careful application 1
• Important to treat into normal-appearing tissue around the lesions 1
• Patient counseling about short- and long-term side effects is essential 1
• Failure of an individual lesion to respond to therapy indicates a need for further evaluation 1
• Consider photodynamic therapy for cosmetically sensitive areas due to superior cosmetic outcomes 1

Cryotherapy remains a cornerstone treatment for actinic keratoses and certain skin cancers, offering an effective option with established protocols and predictable outcomes when applied appropriately.