Alberta Cancer Foundation

The Mohs Process

Step 1: The roots of a skin cancer may extend beyond the visible portion of the tumour. If these roots are not removed, the cancer will recur.

Step 2: The visible portion fo the tumour is removed.

Step 3: A layer of skin is removed and divided into sections. The ACMS surgeon then colour codes each of these sections with dyes and makes reference marks on the skin to show the source of these sections. A map of the surgical site is then drawn.

Step 4: The undersurface and edges of each section are microscopically examined for remaining cancer.

Step 5: If cancer cells are found under the microscope, the ACMS surgeon marks their location onto the “map” and returns to the patient to remove another layer of skin – but only from precisely where the cancer cells remain.

Step 6: The removal process stops when there is no longer any evidence of cancer remaining in the surgical site. Because Mohs surgery removes only tissue containing cancer, it ensures that the maximum amount of healthy tissue is kept intact.