The next step is to apply a sterile cotton ball and cover the dressing with bio-occlusive tape for 24 hours – the time it takes the paste to achieve full penetration. After 24 hours, the patient can return for a conventional, wide excision with standard vertical or bevelled Mohs margins, followed by closure.
However, to take advantage of the paste's immunologic properties, the block of tissue should be left in place for a week or longer, or the main block can be removed, leaving a rim of the fixed tissue in place to stimulate the immune response. Dr. Brooks said the fixed tissue can then be histologically examined to confirm negative margins. For patients with raised lesions, he recommended debulking to create a flat tissue plane and they applying the paste as described.
He also stressed that the Mohs paste does not interfere in any way with conventional melanoma treatment. "About half of my patients end up going to [a cancer center] for excision, sentinel nodes, or other treatment," including interferon, he said. But some patients, after reviewing the comparatively small survival benefit interferon offers and its significant side effects, elect to have the fixed tissue excised and then continue with the practice of node palpation and regular ultrasounds to identify any early disease spread.
Dr. Brooks reported having no relevant financial disclosures.