Imiquimod suitable for certain melanomas, expert says

September 1, 2011

While the standard of care to treat melanomas is surgery, when melanomas appear as in situ or as lentigo malignas, which have the potential for invasion, imiquimod can serve as a first-line option for treatment.

Key Points

Lebanon, N.H. - While the standard of care to treat melanomas is surgery, when melanomas appear as in situ or as lentigo malignas, which have the potential for invasion, imiquimod can serve as a first-line option for treatment.

Michael Shane Chapman, M.D., associate professor of surgery (section of dermatology), Dartmouth-Hitchcock Medical Center, Lebanon, N.H., says the recurrence rate with surgery can range from 5 to 20 percent and that with imiquimod, there is a 90 percent chance of cure and about a 10 percent chance of recurrence.

Dr. Chapman published data on the use of imiquimod in 2007 on 12 cases which found six patients had histologic clearance, two patients demonstrated single atypical melanocytes and four patients showed clinical clearance without histologic confirmation (Spenny ML, Walford J, Werchniak AE, et al. Cutis. 2007;79(2):149-152).

In his own practice, Dr. Chapman has treated melanomas in situ in more than 60 patients. There are 43 patients who have had their melanomas in situ treated with imiquimod and have had been followed for five years or more, with recurrences occurring in four out of 43 patients.

"If the patients fail to clear the melanoma in situ, then we do surgery," Dr. Chapman says. "Some of those 60 patients have had one, two or three previous surgeries with recurrence after surgery. As a treatment modality, surgery wasn't working."

There is a challenge for surgeons if patients have undergone multiple surgeries to remove lesions that are melanoma, Dr. Chapman says.

"If patients have undergone one, two or three surgeries, it is very difficult to see the margins when you cut," he says.

Imiquimod plusses

One of the advantages of having an alternative treatment to surgery for lentigo malignas is that some patients prefer a medical or nonsurgical treatment to produce what they believe is a superior cosmetic result.

"Some patients have very large melanomas on the face, and they do not want an extensive surgical procedure because they are concerned about a disfiguring scar," Dr. Chapman says. "Patients wanted to avoid having surgery and are asking us if we can do anything else."

Imiquimod is also a good fit for treatment if there is a functional component involved in the lesion, where it appears on the eyelid, lip or nose, according to Dr. Chapman. Mucosal genital melanomas can also be a good fit for imiquimod treatment.

At present, Dr. Chapman uses combination therapy in the form of a retinoid for a two-week course followed by imiquimod. He uses the same approach in treating superficial and nodular basal cell carcinomas.

"I found with just using imiquimod that the inflammatory response did not happen briskly enough," Dr. Chapman says. "I found that by adding tazarotene that you can really turn on the switch and get the inflammatory response going by the time you apply the imiquimod. I have found that no patients have been nonresponders if we used a retinoid in combination with imiquimod."

The use of imiquimod is largely well-tolerated by patients, according to Dr. Chapman.

"Most patients don't complain of pain," he says. "Itching or pruritus is the number one complaint."

Following treatment with imiquimod, clinicians do perform a biopsy in the area where the lesion was to ensure that it is gone, Dr. Chapman says.

"There is a 10 percent chance that imiquimod won't work," he says.

When patients are infirm, their health status is poor or they have comorbidities, surgery may not be the best management choice, according to Dr. Chapman.

"If the patient has a pacemaker, is on a blood thinner like Coumadin or is in a nursing home, the patient may not be healthy enough to undergo extensive surgery," Dr. Chapman says.

Certainly, if the lesions appear on body sites like the arm, back or leg, it is preferable to surgically excise the lesion. "Cut it out and close it up if that is the case," Dr. Chapman says.