Nonsurgical techniques for treating skin cancer

Noninvasive skin cancer treatment can be an attractive option for patients, especially in this age of new techniques and pharmaceutical discovery. But with new and exciting advancements often come new and complex questions. Dermatology Times asked Ronald Moy, M.D., a Los Angeles Mohs surgeon and former professor at the University of California, Los Angeles, and Marc D. Brown, M.D., a Mohs surgeon and professor of dermatology and otolaryngology at the University of Rochester Medical School, Rochester, N.Y., to discuss noninvasive skin cancer treatments.

Q: Dr. Moy: For what types of indications do you use imiquimod?

A: Dr. Brown: I utilize it for its Food and Drug Administration (FDA)-approved uses, which are for superficial basal cell cancers less than 2 cm in size on nonfacial areas.

Q: Dr. Moy: When do you use imiquimod, and when do you use the older agents such as 5-FU?

A: Dr. Brown: I've never been a huge fan of 5-FU for anything other than actinic keratoses, mainly because I just never had much success or much benefit. I use 5-FU for actinic keratoses, including even hypertrophic actinic keratoses, and I typically have good results.

I began using imiquimod cautiously - I'm usually not one of these physicians who jumps on the bandwagon right away. I think, over time, I've become more comfortable and have been more enthusiastic about its use.

Q: Dr. Moy: Do you think the reason that imiquimod works better is the mechanism of action: the 5-FU works from the top down and maybe the imiquimod immunologic agent works from the bottom up?

A: Dr. Brown: I believe there is an immune response that occurs at more than just the superficial level, and I think that's probably one of the major reasons why I've had more success with imiquimod than with 5-FU for superficial basal cell carcinoma.

Q: Dr. Moy: What have you found to be the rate of reoccurrence with 5-FU compared to imiquimod?

A: Dr. Brown: I don't think imiquimod has been around long enough to have seen bad recurrences. Even with 5-FU I haven't seen a lot of recurrences and I think that's mainly because it's not a product that is used very much for superficial skin cancer. I think people prefer to use other destructive modalities, such as curettage, electrosurgery or even aggressive cryosurgery as opposed to 5-FU.

I certainly have seen some early recurrences from imiquimod and I have no doubt that we'll see at best an 80 percent to 90 percent success rate with imiquimod; so we're going to be seeing those 10 percent to 20 percent recurrences. There is no perfect treatment; even electrodesiccation and curettage (ED&C) and excisions can give you recurrence rates of up to 10 percent.

Q: Dr. Moy: What are the indications for which you use imiquimod? Are any of these off-label indications?

A: Dr. Brown: There are probably more off label indications than there are on label indications. Probably the most common off label use for me is treating superficial basal cell carcinoma of the face and small nodular basal cell cancers. It's not necessarily my treatment of choice, but again, highly dependent upon the motivation and the desires of the patient.

I think Bowen's (squamous cell cancer in situ) is actually a very good indication for imiquimod. I believe the efficacy is related to the immune response that defines the mechanism of action with imiquimod. I've used imiquimod for Bowen's on genital areas where you're trying to avoid a more potentially mutilating surgical procedure.