Zinc Paste May Help Halt Mohs Recurrences, Despite Its Dangers

SAN DIEGO—Dr. Daniel Siegel applies the zinc chloride paste developed by Dr. Frederic E. Mohs to melanomas the day before he removes them as a kind of insurance policy to reduce the risk of recurrence.

"The paste is wonderful stuff," Dr. Siegel said at a course on Mohs surgery during a meeting sponsored by the American Society for Mohs Surgery.

The paste is not commercially available, but it can be compounded by a pharmacy. Dr. Mohs himself eventually abandoned its use in favor of the fresh tissue technique in the 1950s. In addition to zinc chloride, the paste contains bloodroot (Sanguinaria canadensis) and stibnite, and a little bit lasts a long time. A single jar has lasted about 10 years, he said.

It has not been possible to get a clinical trial of the paste organized because there is no commercial interest, but there is some evidence to suggest its efficacy, said Dr. Siegel, a dermatologist practicing in Smithtown, N.Y.

Dr. Mohs reported better 5-year survival rates for melanoma than are usually reported, even better than those reported by Dr. Wallace H. Clark, originator of the Clark's levels of invasion. He reported 5-year survival of 57% for melanoma patients with a Clark's level III tumor, but Dr. Mohs reported 92%, Dr. Siegel said.

In an experiment with mice that Dr. Siegel was involved in, the investigators reported a markedly positive effect when mice were treated with the paste and then injected with melanoma cells. The mice had melanomas treated with the zinc oxide paste then removed 24 hours later. A second group of mice simply had melanomas excised. Then all the mice were injected in a second site with melanoma cells. Melanomas developed at the challenge site in 69% of the mice treated with excision only, but just 32% of the mice treated with paste (Dermatol. Surg. 1998;24:1021–5). The researchers concluded that the paste was enhancing some kind of immune response.

When Dr. Siegel uses the paste in his practice, he said he is careful to fully inform patients that the treatment is not proven. He also lets them know it is very uncomfortable, and he often uses anesthetic.

Dr. Siegel applies a 50% trichloroacetic acid solution to the lesion before applying the paste, which is painful. Patients often come in the next day complaining that they have a temperature and that their lymph nodes are sore. He then does a wide excision despite the paste, he said.

It is important to warn patients not to touch the lesion and get the paste in an eye. "You have to be very careful and fearful," he said. "Paste can be dangerous."

Despite that, it may be advantageous to use the paste for patients who may be infectious, such as those who are HIV positive, because it probably minimizes infectious agent "splatter," he added.

Most importantly, there is no reason to believe that the use of the paste may be harmful, since the tumor is being removed anyway, Dr. Siegel said.

In fact, he is not the only Mohs surgeon who uses the paste for melanoma cases.

Dr. Kenneth Gross of San Diego, one of the organizers of the Mohs course, said that he has used it for patients who are having a sentinel node procedure.

"Do I know this is helping? I absolutely do not. [But] we are killing and immobilizing cells and I don't see how that could be any problem," he said.

SAN DIEGO—Dr. Daniel Siegel applies the zinc chloride paste developed by Dr. Frederic E. Mohs to melanomas the day before he removes them as a kind of insurance policy to reduce the risk of recurrence.

"The paste is wonderful stuff," Dr. Siegel said at a course on Mohs surgery during a meeting sponsored by the American Society for Mohs Surgery.

The paste is not commercially available, but it can be compounded by a pharmacy. Dr. Mohs himself eventually abandoned its use in favor of the fresh tissue technique in the 1950s. In addition to zinc chloride, the paste contains bloodroot (Sanguinaria canadensis) and stibnite, and a little bit lasts a long time. A single jar has lasted about 10 years, he said.

It has not been possible to get a clinical trial of the paste organized because there is no commercial interest, but there is some evidence to suggest its efficacy, said Dr. Siegel, a dermatologist practicing in Smithtown, N.Y.

Dr. Mohs reported better 5-year survival rates for melanoma than are usually reported, even better than those reported by Dr. Wallace H. Clark, originator of the Clark's levels of invasion. He reported 5-year survival of 57% for melanoma patients with a Clark's level III tumor, but Dr. Mohs reported 92%, Dr. Siegel said.

In an experiment with mice that Dr. Siegel was involved in, the investigators reported a markedly positive effect when mice were treated with the paste and then injected with melanoma cells. The mice had melanomas treated with the zinc oxide paste then removed 24 hours later. A second group of mice simply had melanomas excised. Then all the mice were injected in a second site with melanoma cells. Melanomas developed at the challenge site in 69% of the mice treated with excision only, but just 32% of the mice treated with paste (Dermatol. Surg. 1998;24:1021–5). The researchers concluded that the paste was enhancing some kind of immune response.

When Dr. Siegel uses the paste in his practice, he said he is careful to fully inform patients that the treatment is not proven. He also lets them know it is very uncomfortable, and he often uses anesthetic.

Dr. Siegel applies a 50% trichloroacetic acid solution to the lesion before applying the paste, which is painful. Patients often come in the next day complaining that they have a temperature and that their lymph nodes are sore. He then does a wide excision despite the paste, he said.

It is important to warn patients not to touch the lesion and get the paste in an eye. "You have to be very careful and fearful," he said. "Paste can be dangerous."

Despite that, it may be advantageous to use the paste for patients who may be infectious, such as those who are HIV positive, because it probably minimizes infectious agent "splatter," he added.

Most importantly, there is no reason to believe that the use of the paste may be harmful, since the tumor is being removed anyway, Dr. Siegel said.

In fact, he is not the only Mohs surgeon who uses the paste for melanoma cases.

Dr. Kenneth Gross of San Diego, one of the organizers of the Mohs course, said that he has used it for patients who are having a sentinel node procedure.

"Do I know this is helping? I absolutely do not. [But] we are killing and immobilizing cells and I don't see how that could be any problem," he said.

SAN DIEGO—Dr. Daniel Siegel applies the zinc chloride paste developed by Dr. Frederic E. Mohs to melanomas the day before he removes them as a kind of insurance policy to reduce the risk of recurrence.

"The paste is wonderful stuff," Dr. Siegel said at a course on Mohs surgery during a meeting sponsored by the American Society for Mohs Surgery.

The paste is not commercially available, but it can be compounded by a pharmacy. Dr. Mohs himself eventually abandoned its use in favor of the fresh tissue technique in the 1950s. In addition to zinc chloride, the paste contains bloodroot (Sanguinaria canadensis) and stibnite, and a little bit lasts a long time. A single jar has lasted about 10 years, he said.

It has not been possible to get a clinical trial of the paste organized because there is no commercial interest, but there is some evidence to suggest its efficacy, said Dr. Siegel, a dermatologist practicing in Smithtown, N.Y.

Dr. Mohs reported better 5-year survival rates for melanoma than are usually reported, even better than those reported by Dr. Wallace H. Clark, originator of the Clark's levels of invasion. He reported 5-year survival of 57% for melanoma patients with a Clark's level III tumor, but Dr. Mohs reported 92%, Dr. Siegel said.

In an experiment with mice that Dr. Siegel was involved in, the investigators reported a markedly positive effect when mice were treated with the paste and then injected with melanoma cells. The mice had melanomas treated with the zinc oxide paste then removed 24 hours later. A second group of mice simply had melanomas excised. Then all the mice were injected in a second site with melanoma cells. Melanomas developed at the challenge site in 69% of the mice treated with excision only, but just 32% of the mice treated with paste (Dermatol. Surg. 1998;24:1021–5). The researchers concluded that the paste was enhancing some kind of immune response.

When Dr. Siegel uses the paste in his practice, he said he is careful to fully inform patients that the treatment is not proven. He also lets them know it is very uncomfortable, and he often uses anesthetic.

Dr. Siegel applies a 50% trichloroacetic acid solution to the lesion before applying the paste, which is painful. Patients often come in the next day complaining that they have a temperature and that their lymph nodes are sore. He then does a wide excision despite the paste, he said.

It is important to warn patients not to touch the lesion and get the paste in an eye. "You have to be very careful and fearful," he said. "Paste can be dangerous."

Despite that, it may be advantageous to use the paste for patients who may be infectious, such as those who are HIV positive, because it probably minimizes infectious agent "splatter," he added.

Most importantly, there is no reason to believe that the use of the paste may be harmful, since the tumor is being removed anyway, Dr. Siegel said.

In fact, he is not the only Mohs surgeon who uses the paste for melanoma cases.

Dr. Kenneth Gross of San Diego, one of the organizers of the Mohs course, said that he has used it for patients who are having a sentinel node procedure.

"Do I know this is helping? I absolutely do not. [But] we are killing and immobilizing cells and I don't see how that could be any problem," he said.