Cryotherapy in the management of premalignant and malignant conditions of the esophagus

Table 3 Radiofrequency ablation vs cryotherapy

	Radiofrequency ablation	Cryotherapy
Mechanism of action	Bipolar electrode delivering radiofrequency energy to mucosa which generates heat and causes a uniform thermal injury on contact	Rapid freeze and thaw cycles cause immediate effects of slowing cellular metabolism and freezing intracellular water. Subsequently, ice formation results in disruption of cellular membranes and organelle dysfunction and eventually cellular apoptosis.
Maximal depth of injury	Mucosa (500-1000 microns)	Depends on the dose delivered; upto submucosa
Eradication of metaplasia	66.7%-100 %	41.3%-60% with cryospray; 84%-100% with cryoballoon
Eradication of dysplasia	87.5%-100%	78.8%-90% with cryospray; 92%-100% with cryoballoon
Post procedure pain requiring analgesics	4 d	2 d
Side effects	Esophageal strictures in 10.2%, bleeding 1.1%, perforation 0.2%	Esophageal strictures in 0%-12.5%, bleeding in 2 cases, perforation in 3 cases
Durability	CE-D 98% and CE-IM 91% at 3 yr	CE-D 92%, and CE-IM 81% at 5 yr (with cryospray only, cryoballoon data not available)
Recurrent metaplasia	16.10%	13.30%
Recurrent dysplasia	2.60%	3.60%
Recurrent high grade dysplasia or cancer	1.40%	1.30%

CE-D: Complete eradication of dysplasia; CE-IM: Complete eradication of intestinal metaplasia.