Abstract and Introduction
Abstract
Aim To report the outcome at 5-year follow-up of a defined series of patients with primary periocular basal cell carcinoma treated by cryotherapy using a nitrous oxide probe.
Methods A prospective, non-comparative, interventional case series. One hundred primary periocular basal cell carcinomas were treated with a double freeze–thaw cycle nitrous oxide contact cryotherapy probe. Inclusion criteria were clinically well-defined primary periocular basal cell carcinomas with maximum diameter of 8 mm. The main outcome measure was histologically proven recurrence rate at 5-year follow-up.
Results Kaplan–Meier survival analysis showed a 5-year recurrence rate of 8%. Cox regression analysis revealed no correlation between tumour site, tumour size, cryotherapy freeze time and recurrence (p=0.60, p=0.86 and p=0.71, respectively). Thirty-six per cent of patients were lost to follow-up at 5 years following treatment.
Conclusion The results of this series suggest that nitrous oxide probe cryotherapy for primary periocular basal cell carcinomas up to 8 mm diameter has a recurrence rate of ~8%. Cryotherapy has certain advantages over surgical removal of tumours of this size in the periocular region, but careful follow-up is advisable.
Introduction
Cryotherapy is an established treatment modality for basal cell carcinomas. The features of cryotherapy depend on a rapid freeze and a slow thaw. Temperatures to below −30°C are necessary to destroy cancer cells. Liquid nitrogen, nitrous oxide and carbon dioxide are used as freezing agents. The literature on liquid nitrogen cryotherapy for periocular basal cell carcinomas is extensive. Reported cure rates vary between 92% and 100%. However, it is difficult to draw definite conclusions given the different freeze–thaw cycle characteristics, application techniques and follow-up times.
Nitrous oxide has been used as a cryoagent in the treatment of malignant tumours and other conditions such as trichiasis. We believe this to be the first report of the outcome at 5-year follow-up of nitrous oxide contact probe cryotherapy as a treatment for primary periocular basal cell carcinomas.