Topical Ascorbic Acid for Treatment of Squamous Cell Skin Cancer

Importance:

Skin cancer is the most common cancer in the United States, with more people diagnosed each year than all other cancers combined. Basal cell and squamous cell cancers are the most common forms with an estimated 6-7 million cases diagnosed annually. Costs of treating these cancers in the U.S. are estimated at $9-10 billion annually. Task force consensus guidelines suggest Mohs surgery as the treatment of choice, and as the single most precise and effective treatment method. However, cost and issues of cosmesis are principal disadvantages. Previous studies show the effectiveness of a topical solution of ascorbic acid in the treatment of BCC. This study extends previous work to evaluate efficacy in the treatment of SCC of the skin.

Objective:

To evaluate efficacy of a therapeutic regimen in treating squamous cell cancer, consisting of 30% ascorbic acid in 95% dimethylsulfoxide topically applied at home by patients twice a day for 8 weeks, vs 5% imiquimod cream which is an FDA approved treatment for SCC.

Design, Setting, and Participants:

This study was carried out in accordance with principles of the Declaration of Helsinki. Detailed informed consent was obtained from each patient.

Eligible participants of any age had histologically confirmed primary, previously untreated, nodular or superficial SCC. Patients with cancers larger than 2 cm or deeper than 2 mm were excluded from the study. Imiquimod was applied once daily for 5 days per week as per manufacturer instructions for treatment of SCC. Patients were randomly assigned to treatment group. Participants and outcome assessors were blinded to treatment protocol. Patients were seen at initial visit, 4 weeks, 8 weeks, and six weeks after treatment conclusion for final biopsy. The AA treatment was a solution while the IMQ a cream, however participants were simply told they would be receiving a topical treatment with instructions on how to apply, thus the blinding was intact.

Main Outcomes and Measures Number of lesions out that were cancer free after 8 wks of treatment.