Effectiveness of Cryotherapy for Oral Precancers – A Pilot Study

Objectives: Early treatment of oral precancers may prevent lesions from becoming cancerous, and thus is the key in oral cancer control. Few study groups have used topical treatment for oral precancers; however, most have small sample size or limited clinical follow-up. Therefore, the effectiveness has yet to be determined. This pilot study aims to use a topical agent for the treatment of pathology-proven low-grade lesions (LGL) and to assess the clinical outcome.

Methods: From April 2014, we recruited 20 (9 males, 11 females) eligible patients with clinically and pathologically LGLs. Under local anesthesia, liquid nitrogen (Brymill Cry-AC Cryogenic Systems, Ellington, CT) was applied 3 times for 10seconds each, for each 10mm lesion area. The average interval between treatments was 4-6 weeks. Patients are on 6-month follow-up after clinically complete resolution (CR) was reached.
Results: All lesions were white coloured and 4 had less than 20% redness. Most were on the tongue (10), followed by gingiva (6), palate (2), lip (1), and buccal mucosa (1). LGLs had an average size of 18.6±13mm (min-max, 8-60mm) mm. Ten had no dysplasia, 2 had mild, and 8 had moderate dysplasia. The mean number of treatments was 2.6±1.6 (min-max, 1-7); follow-up time was 11.5 (min-max, 0.9-24) months. Lesions <20mm (n=14) were treated 1-2 times with 6 reaching CR, 6 partially resolving (PR), and 2 recurring to original size. Lesions ≥20mm were treated more than 3 times with 4 CRs and 2 PRs, with sizes reduced by 80%. All patients recovered well with mild pain that resolved within 3 weeks post-treatment.
Conclusions: Cryotherapy provides an easy alternative to control LGLs. Further study with larger sample sizes and longer follow-up is necessary to monitor its long-term effectiveness. Investigation of molecular risk of these pathologically and clinically similar lesions may be warranted to predict the effectiveness of cryotherapy.