Mohs surgery is well known in the field of dermatology for being the most effective surgical procedure for eliminating skin tumors. However, there is always room for improvement. In the case of melanoma treatment, some doctors are once more exploring the value of zinc chloride paste as a supplement to surgical excision of cancer.
What’s in Zinc Chloride Paste?
As the name suggests, the main active ingredient in this topical preparation is zinc chloride – a compound of zinc and chlorine. This combination of substances is actually quite poisonous and has been used as everything from an antiseptic to an embalming ingredient. Dried, powdered bloodroot is also mixed into the paste created for use in melanoma chemosurgery. Bloodroot has the ability to kill cells and is sometimes used as an anti-fungal and anti-bacterial agent. The inert ingredient used to make up the bulk of the paste is stibnite – a compound of antimony and sulfur.
How Does It Affect Melanoma Cells?
Abnormal tissue is slightly more susceptible to absorbing zinc chloride than normal tissue. So, the highly toxic effect of the paste is concentrated in the tumor cells – although it may affect surrounding healthy tissue to some extent as well. Bloodroot also has an effect on cancer cells that prompts them to self-destruct. The paste is powerful enough to penetrate thick melanoma tumors that go all the way down to the bone.
Finally, the paste appears to trigger an immune response. According to one study conducted in the late 90s, there is a slight chance that operating on a primary melanoma tumor may increase the risk of the cancer recurring and/or spreading throughout the body. Using paste to kill cancer cells deep in the tissue and stimulate the immune system may help prevent this unintended side effect of Mohs surgery.
How the Paste is Used
For the paste to be effective, it must be applied to an open wound. The substance doesn’t absorb well through intact skin. So, the suspected area of cancerous skin is removed and the paste is applied to the biopsy site. The pasted area is covered with a sterile cotton ball fixed in place with tape. It is left on for 24 hours so the ingredients can fully penetrate the cancerous tissue. The paste may be left in place longer to trigger an immune response in some cases. Inflammation and discomfort are common side effects of this treatment. After the paste has done its work, the remaining steps of the Mohs surgery are completed and the wound is closed.