How many times should actinic keratosis (AK) or seborrheic keratosis (SK) be treated with cryotherapy?

Cryotherapy Treatment Protocol for Actinic Keratosis and Seborrheic Keratosis

For actinic keratosis (AK), a single cryotherapy treatment with a 5-20 second freeze duration is typically sufficient, with 77% of patients achieving complete clearance after just one treatment, though up to four treatments separated by 6-12 weeks may be needed for resistant lesions. 1

Actinic Keratosis Treatment Protocol

Freeze Duration Based on Location and Thickness

• Face and Scalp (standard protocol):

  • Thin lesions: 5-10 seconds freeze time
  • Moderate lesions: 10-20 seconds freeze time
  • Thick/hyperkeratotic lesions: >20 seconds freeze time 1

• Treatment effectiveness by duration:

  • <5 seconds: 39% cure rate
  • 5-20 seconds: 69% cure rate

  • 20 seconds: 83% cure rate 1

Number of Treatment Sessions

• First-line approach: Single treatment session achieves 75% complete response rate at 3 months 1
• Follow-up assessment: Evaluate at 6-12 weeks after treatment
• Resistant lesions: May require up to 4 treatment sessions separated by 6-12 weeks 1
• Important note: 77% of patients need only one treatment to achieve clearance 1

Freeze-Thaw Cycles

• Standard protocol: Single freeze-thaw cycle (68% response) 1
• For thick or suspicious lesions: Double freeze-thaw cycle (75% response) 1

Seborrheic Keratosis Treatment Protocol

For seborrheic keratosis, a single treatment with longer freeze time is typically sufficient:

• Standard protocol: 10-15 second freeze time
• Thicker lesions: May require a second treatment session if incomplete resolution

Treatment Considerations and Pitfalls

Potential Side Effects

• Common side effects include soreness, blistering, pigmentary change, and scarring 1
• Patients often prefer PDT over cryotherapy due to these side effects, but cryotherapy remains more effective for thick lesions (69% vs 52% response) 1

Special Anatomical Considerations

• Periocular lesions: Use contact probe rather than spray technique
• Ears: Consider more aggressive treatment due to higher risk of SCC progression 2
• Below knee: Consider alternative treatments due to poor healing concerns 2

When to Consider Alternative Treatments

• Multiple lesions: Consider field therapy with topical agents instead
• Cosmetically sensitive areas: PDT may provide superior cosmetic outcome 3
• Non-responsive lesions: Any lesion failing to respond to cryotherapy requires biopsy to rule out squamous cell carcinoma 2

Follow-up Protocol

• Evaluate response 8-12 weeks after treatment 2
• Schedule regular skin examinations every 6-12 months 2
• Emphasize sun protection to prevent new lesions 2

Cryotherapy remains a highly effective first-line treatment for isolated AK and SK lesions, with the advantage of requiring only a single session in most cases, making it particularly suitable for patients who may have difficulty adhering to longer treatment regimens 4.