Imiquimod Effectiveness for Clearance of Lentigo Maligna Depends on Dose and Intensity
A recent systematic review published in The Journal of The American Academy of Dermatology, examined the clearance rates in patients with lentigo maligna treated with imiquimod and analyzed the factors that can impact tumor clearance. Lentigo maligna (LM) is the most commonly diagnosed subtype of melanoma in situ, especially in sun-damaged skin of the head and neck. There are surgical and non-surgical interventions to remove LM, but due to concerns about scarring and other long term side effects, they may not be the best choice for all patients. Imiquimod is a topical immunomodulator approved by the FDA for treating actinic keratoses, superficial basal cell carcinomas and anogential warts. Imiquimod has also been used off-label to treat LM.
There are varying results in published studies on the effectiveness of using imiquimod for treating LM with reported clearance rates ranging from 60% to 100% and a wide variation in treatment protocols. This systematic review was a quantitative analysis of 45 studies published since 2000. The authors determined that cumulative dose and treatment intensity (number of applications per week) significantly predicted histologic and clinical clearance after imiquimod treatment for LM. The likelihood of histologic and clinical clearance was significantly higher in tumors treated with more than 60 applications of imiquimod, and with more than 5 applications per week. Tumor size did not predict either clinical or histologic clearance.
The authors concluded that imiquimod offers reasonable alternative histologic and clinical clearance rates for both primary and recurrent/previously treated LM where there are concerns about a surgical approach to treatment. Overall, he clinical and histologic clearance rates were 78.3% and 76.2%, respectively. There is a threshold for the treatment intensity and cumulative dose needed to produce an adequate inflammatory response to effectively treat LM.
By: Wendy Meltzer, MPH
Adapted from the original article.
[image by Ellen van Deelen]