Last month a Clinical Practice Guide for management of BCCs and SCCs was produced with Federal Government funding by the Australian Cancer Network. The Australasian College of Skin Cancer Medicine (ACSCM) is concerned that the guide is encouraging doctors to use treatment modalities that are suboptimal including usage of medications that are not endorsed by the Therapeutic Goods Administration (TGA).
Three authors of this report have chosen to contradict the TGA by stating that imiquimod topical is “suitable” for indications outside of TGA approval. The authors of the section relating to imiquimod have been involved in studies funded by the manufacturers of imiquimod. They encourage imiquimod to be considered for the management of nodular BCCs. This is an indication not approved by the TGA. Only one study is cited to justify encouraging doctors to ignore TGA restrictions. It is a small study in which 41 of 56 patients (73%) demonstrated a clearance of their nodular BCC following imiquimod treatment. It was a study undertaken in 2002 by one of the guideline authors and funded by imiquimod manufacturers.1
This study is much smaller than the robust study of imiquimod for superficial BCCs that was instrumental in TGA approving imiquimod usage for superficial BCCs.2
The guide failed to cite other studies using imiquimod for nodular BCCs. For example, a study by Sterry3 demonstrated a 76% to 87% efficacy with imiquimod being used for superficial BCCs but only 50 to 65% when imiquimod was used for nodular BCCs. A further study of 19 cases of nodular BCC demonstrated successful treatment in only 10 patients (53%).4 A Cochrane review of management of BCCs in 20075 also commented on the lack of large quality studies to validate usage of imiquimod for nodular BCCs.
One can only expect imiquimod to be effective in 50 to 73% of cases of nodular BCC. The guide only quoted the most favourable figure. In contrast one expects appropriate surgical excision to be effective for over 95% of nodular BCCs.
In short, imiquimod is not adequately effective for nodular BCCs. ACSCM endorses the TGA approved indications for imiquimod and does not endorse doctors using imiquimod outside of TGA recommended indications.
The Guide also endorses imiquimod being used for squamous cell carcinoma in situ (Bowens), another non approved indication. The only study cited to justify this non approved usage by doctors was a study of merely 15 patients having their Bowens treated with imiquimod.6 Even the study authors acknowledge that this study in itself does not justify imiquimod being considered a recognised therapy for Bowens.
We do not know why the authors of this guide have chosen to suggest doctors over rule TGA restrictions. ACSCM supports the TGA and strongly encourages doctors not to use pharmaceutical agents outside of TGA approved indications.
ACSCM recommends that this guide be withdrawn immediately and revised so as only approved evidence - based treatments are recommended by the guide. By following the current guide Australians risk having their skin cancers managed poorly with an official guide being used to justify the poor treatment choices.
Associate Professor Anthony J. Dixon MB BS FACRRM FACSCM PhD
Australasian College of Skin Cancer Medicine
1. Shumack S, Robinson J, Kossard S, Golitz L, Greenway H, Schroeter A, Andres K, Amies M, Owens M. Efficacy of topical 5% imiquimod cream for the treatment of nodular basal cell carcinoma: comparison of dosing regimens. Arch Dermatol 2002;138:1165-71.
2. Geisse J, Caro I, Lindholm J, Golitz L, Stampone P, Owens M. Imiquimod 5% cream for the treatment of superficial basal cell carcinoma: results from two phase III, randomized, vehicle-controlled studies. J Am Acad Dermatol 2004;50:722-33.
3. Sterry W, Ruzicka T, Herrera E, Takwale A, Bichel J, Andres K, Ding L, Thissen MR. Imiquimod 5% cream for the treatment of superficial and nodular basal cell carcinoma: randomized studies comparing low-frequency dosing with and without occlusion. Br J Dermatol 2002;147:1227-36.
4. Peris K, Campione E, Micantonio T, Marulli GC, Fargnoli MC, Chimenti S. Imiquimod treatment of superficial and nodular basal cell carcinoma: 12-week open-label trial. Dermatol Surg 2005;31:318-23.
5. Bath-Hextall FJ, Perkins W, Bong J, Williams HC. Interventions for basal cell carcinoma of the skin. Cochrane Database Syst Rev 2007:CD003412.
6. Patel GK, Goodwin R, Chawla M, Laidler P, Price PE, Finlay AY, Motley RJ. Imiquimod 5% cream monotherapy for cutaneous squamous cell carcinoma in situ (Bowen's disease): a randomized, double-blind, placebo-controlled trial. J Am Acad Dermatol 2006;54:1025-32.