Surgery Versus Combined Treatment With Curettage and Imiquimod for Nodular Basal Cell Carcinoma

Basal cell carcinoma (BCC) is a slow-growing, locally invasive malignant epidermal skin tumour. It is the most common malignant disease in Caucasians, representing approximately 80% of all cases of skin cancer and is therefore an important health problem. In the Netherlands incidence rates are 165 for men and 157 for women per 100.000 person-years, and these rates are rising with 3-10% every year. A simplified histological classification of BCCs includes the following three subtypes: nodular, superficial and infiltrative variants, with the nodular variant being the most frequent type. Although a characteristic feature of BCCs is their low risk to metastasize, if untreated they may be locally invasive and may induce considerable functional and cosmetic morbidity. The gold standard treatment of all histological BCC subtypes is surgical excision (SE), but not all patients are eligible for surgery. In patients with multiple BCCs and older patients, surgery may lead to significant morbidity, and in some cases, it may result in disfiguring scarring. For these reasons and to reduce workload and costs in the healthcare system, there is a growing demand for alternative, non-invasive, treatments. An advantage of non-invasive treatment options is that they can be performed by other healthcare professionals, such as general practitioners and specialized nurses. For treatment of superficial BCCs (sBCC) non-invasive treatments, such as topical imiquimod (IMQ), 5-fluorouracil (5-FU) or photodynamic therapy (PDT) are already commonly used. Our group investigated the efficacy of those three therapies and found that after 3 years, BCCs treated with IMQ had a significant lower risk of recurrence, compared to the other therapies. A recent study suggests that IMQ, besides being an immune-response modifier, also directly inhibits sonic hedgehog (SHH) signalling, the most important pathway active in BCCs. This targeted effect of IMQ very likely explains the superior therapeutic effect.