Topical Green Tea Ointment in Treatment of Superficial Skin Cancer

Overview

Basal cell carcinoma (BCC) is the most frequently occurring nonmelanoma skin cancer in Caucasians, representing approximately 80% of cases. Incidence rates for men and women in the Netherlands are 165 and 157 per 100,000 person-years respectively and are still rising 3-10% annually. In 2009, the lifetime risk for developing a first histologically confirmed BCC for men was approximately 1 in 5 (21%) and for women it was 1 in 6 (18%). A simplified classification of BCC includes the following three histological subtypes: nodular (40,6), superficial (30,7%) and infiltrative BCC (28,7%). Superficial BCCs (sBCCs) differ from the other subtypes as they tend to appear at a younger age, usually occur on the trunk and are often multiple. This subtype has the fastest growing incidence. A characteristic feature of BCCs is their low risk to metastasize, though if untreated they may induce considerable functional and cosmetic morbidity as they are locally invasive. Surgery is the first treatment of choice for BCC. However due to the rising incidence and the extensive workload this entails, a non-invasive topical treatment is often chosen for sBCC as they grow down from the epidermis into the superficial dermis and therefore are easily accessible for topical treatment. Photodynamic therapy (PDT), imiquimod cream or 5-fluorouracil cream are available topical treatments for sBCC however their tumour free survival rates are not equal to the higher tumour free survival rates of surgical treatment. Next to the efficacy, the now available topical treatments are associated with local skin reactions at the treatment site, mainly erythema and erosion (imiquimod cream and 5-fluorouracil cream) or pain and burning sensation (PDT). This creates the need for additional or alternative non-invasive topical treatments. The active constituents of green tea are promising as they are supported to have anti-BCC-carcinogenesis effects by several epidemiological, cell culture and animal studies. The so-called polyphenols known as catechins are the active constituents of green tea and the catechin epigallocatechin-3-gallate (EGCG) is the major and most active catechin. EGCG is thought to have a cytotoxic effect on skin cancer cells and has the availability of inhibition of cell growth and induction of apoptosis. It is also suggested that EGCG plays a role in inactivation of β-catenin signalling, an important component of the WNT pathway. Sinecatechins 10% ointment (Veregen®) is a standardized extract of green tea leaves of the species Camellia sinensis, containing mainly green tea polyphenols, particularly catechins (more than 85%). The lead catechin in sinecatechins ointment is EGCG. It is approved by the US Food and Drug Administration (FDA) for genital warts in adults. There are no clinical trials on human subjects with topical EGCG on sBCC yet. With this trial we are the first to try to validate the anti-carcinogenic potentials of topical EGCG in humans with sBCC. We assess the effectiveness of sinecatechins 10% (Veregen®) versus placebo for the topical treatment of sBCCs.