Basal cell carcinoma
Basal cell carcinoma
Much of the primary literature utilizing cryotherapy to treat basal cell carcinoma is over 30 years old. One study of 628 basal cell carcinomas treated between 1980 and 1984 reported a 5-year cure rate of 99%.23 The authors note that most of the cancers were
“small (<0.5 cm) to medium (0.5–2.0 cm)” or superficial. Additionally, lesions located in critical anatomic locations—such as medial canthus—were excluded. The treatment technique sometimes included preoperative treatment with a local anesthetic and curettage. Depending on the size and thickness of the tumors, freeze time varied from 40 to 90 seconds, and the authors preferred to include repeated freeze–thaw cycles.
A 2003 review of uncontrolled prospective studies of basal cell carcinomas treated with cryosurgery reported recurrence rates ranging from 0% to 21% for follow-up at 6 months to 10 years.24 If the single study of 19 patients with eyelid tumors is excluded, the highest reported recurrence rate is 8.2%. Cosmesis was quantitatively evaluated in only two studies, but was generally commented on as “acceptable” to “excellent.” All studies were assigned a C grade, per Sackett’s rules of evidence, indicating lack of randomization, placebo control, or blinding, and were case reports and case series.25
In addition to problems with study design noted above, at least one author has challenged the previously reported high cure rates for two other reasons.26 First, previous studies were not stratified based on histological subtype. In addition, the treatment techniques reported in the initial publications likely differ significantly from how cryotherapy is currently used. Most contemporary dermatologists are unlikely to debulk a tumor with curettage or electrosurgery prior to cryotherapy. Furthermore, contemporary dermatologists probably do not utilize freeze cycles as long as those previously reported. Accordingly, the cure rates from older studies may not be replicated in contemporary practices.