Basal Cell Carcinoma (BCC) is the most common cancer in the United States. It afflicts 2 to 3 million Americans each year, more than all non-skin cancers combined. Notably, US active duty military and Veterans are at higher risk for developing BCC, with at least 49,000 Veterans treated for the disease in 2010. BCC usually occurs on the face and hence can result in high morbidity and disfigurement with substantial associated expense both in the overall population (estimated at $3 billion in 2013), and among Veterans (estimated at $86 million in 2012) served by Veterans Health Administration (VHA). Morbidity and disfigurement are particularly important due to their impact on key facial structures (e.g. eyelids, nose, etc). After BCC diagnosis, subsequent monitoring for BCC (ex. return specialist visits for dermatologic examinations) and treatments following diagnosis (surgeries most commonly, but also radiation therapy or chemotherapy) significantly contribute to healthcare costs. This large incidence, morbidity, and cost could potentially be minimized through preventative measures, but currently there are no treatment options for preventing BCC.

The primary goal of this study is to investigate the efficacy of topical Imiquimod (IMQ) for the prevention of BCC. IMQ, a topical immunostimulatory medication with a very low rate of side effects, is potentially capable of meeting this need. IMQ is already FDA approved as a safe and effective treatment for superficial BCC, as well as for actinic keratosis and nodular BCC. The investigators have reason to suspect that IMQ may also be able to prevent the occurrence of BCC or to destroy clinically-unrecognized precursors of BCC, thereby reducing the risk of BCC development.

CSP #2019 is an intent-to-treat, split-plot design, multicenter randomized trial with two levels of randomization. The patient level of randomization is the primary intervention: a double-blind comparison of IMQ vs. placebo cream for preventing BCC on the face at one year and over 3 years after therapy. VA has developed an automated text message service application called Annie that can send automated treatment reminders to Veterans if they register/enroll in Annie and consent to receive Annie messages. In the center level of randomization, 9 of 17 participating VA centers will be randomly assigned to offer the participants daily study treatment reminders via the Annie app. The remaining centers will not offer daily reminders via Annie. Participants in each center will be randomly allocated (1:1) to either topical IMQ or placebo (vehicle control cream). Study participants, staff and study dermatologists will not know which treatment the participant receives. Participants will apply IMQ or placebo cream to the face daily at bedtime for a total of 12 weeks. In-person visits will occur at weeks 6 and 12 during treatment, and at months 6, 12, 18, 24, 30, and 36 during active follow-up to assess study outcomes. Full skin exams will be performed and other outcome data collected at every scheduled in-person visit. Telephone interviews will occur every week through week 13 (other than weeks 6 and 12, due to an in-person visit), as well as at months 9, 15, 21, 27, and 33. Follow-up will include 3 years of active follow-up with participants, followed by 1 year of passive follow-up during which study outcome information will only be captured from medical records.