According to the British Association of Dermatologists, 15% to 25% of actinic keratosis (AK) lesions spontaneously resolve during a one-year period. However, AK lesions may develop into invasive squamous cell carcinoma (SCC) if left untreated. The rate of progression from AK to SCC is unknown. Mathematical models derived from a study predicted that for an individual with an average of 7.7 AKs, the probability of developing an SCC at the same or nearby site within a 10-year period is approximately 10. The risk of malignant transformation is higher in patients who are immunocompromised. In Canada, 74,100 new cases of non-melanoma skin cancers (NMSCs) and 270 deaths due to these cancers were predicted for 2011.
AK typically manifests as 2 mm to 6 mm scaly macules, papules, or plaques that are skin to reddish-brown in colour, and may be flat or thickened (hyperkeratotic)., Patients with AK are usually referred to dermatologists and diagnosis is frequently made on clinical appearance alone. A skin biopsy may be required when there is clinical doubt or suspicion of invasive malignancy., Detectable AK may be associated with a field change where the surrounding skin is also altered and subclinical lesions may be present. Patient input to the CADTH Common Drug Review (CDR) suggests that cosmetic issues are a major concern for patients, and this can have a negative impact on self-confidence.
The submitted product is a combination of two topical therapies, 5-fluorouracil 0.5% (5-FU) and salicylic acid 10% (SA). 5-FU is an antimetabolite that is already approved as monotherapy for treatment of AK, although at a concentration of 5%. SA is a keratolytic, and the theory behind its use is to improve penetration of the combination in hyperkeratotic AK. The 5-FU/SA combination under review is administered once daily to affected lesions, until lesions have cleared or for a maximum of 12 weeks. It is indicated for the management of grade I/II hyperkeratotic AK. [Table: see text]
The objective of this report was to perform a systematic review of the beneficial and harmful effects of 5-FU (0.5%) combined with SA 10% applied topically once daily for the topical treatment of slightly palpable and/or moderately thick hyperkeratotic actinic keratosis (grade I/II) of the face, forehead, and balding scalp in immunocompetent adult patients.
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