Interventions for basal cell carcinoma of the skin

Abstract

Background: Basal cell carcinoma (BCC) is the most common skin malignancy in humans. BCCs are defined as slow-growing, locally invasive, malignant (but not life threatening), epidermal skin tumours which mainly affect white skinned people. The first line treatment is usually surgical excision, but numerous alternatives are available.

Objectives: To assess the effects of treatments for basal cell carcinoma.

Search strategy: We searched the Cochrane Database of Systematic Reviews (2002 issue 1) and Cochrane Controlled Trials Register (2002 issue 1), the Cochrane Skin Group Specialised Register (January 2002), MEDLINE (from 1966-2002), EMBASE (from 1980-2002), the Mega Register of Controlled trials and the National Research Register (2002 issue 1). In addition the cited references of all trials identified and key review articles were searched. Pharmaceutical companies were contacted where appropriate for reviews or unpublished trials.

Selection criteria: Inclusion criteria were adults with one or more histologically proven, primary basal cell carcinoma. The primary outcome measure was recurrence at 3- 5 years, measured clinically. The secondary outcome included early treatment failure within 6 months, measured histologically. Adverse effect of treatment was evaluated by reviewing aesthetic appearance (to patient and blinded observer) and pain during and after treatment.

Data collection and analysis: Study selection and assessment of methodological quality were carried out by two independent reviewers.

Main results: 19 studies (13 published and 6 abstracts) were identified which include 7 broad therapeutic categories. Only one RCT of surgery versus radiotherapy had primary outcome data at four years, which showed that there were significantly more persistent tumours and recurrences, measured histologically, in the radiotherapy group as compared to the surgery group, which translates to an odds ratio of 0.09 (95%CI, 0.01 to 0.67) in favour of surgery. Cryotherapy, although convenient and less expensive than surgery, showed no significant difference in recurrences at one year, measured clinically, when compared to surgery, OR 0.23 (0.01 to 6.78). However when radiotherapy was compared to cryotherapy there were significantly more recurrences at one year, measured histologically, in the cryotherapy group, this translates to an odds ratio of 14.80 (95%CI, 3.17 to 69) in favour of radiotherapy. Preliminary studies suggest a high success rate (87-88%) for imiquimod in the treatment of superficial BCC using a once-daily regimen for 6 weeks and a useful (76%) treatment response when treating nodular BCC for 12 weeks, when measured histologically. However this cream has not been compared to surgery.

Reviewer's conclusions: There has been very little good quality research on efficacy of the treatment modalities used. Most of the trials have looked only at BCCs in low risk areas. Surgery and radiotherapy appear to be the most effective treatments with surgery showing the lowest failure rates. Other treatments might have some use but few have been compared to surgery. Imiquimod emerged as a possible new treatment although it has not been compared to surgery or any other modality.