Mohs Surgery - History of the Technique

Mohs Micrographic Surgery (MMS) was created by Dr. Frederic E. Mohs, in 1936 at the University of Wisconsin, as an 'in situ' way of removing skin cancer. In 1941, Frederick Mohs published his results suing a 'chemosurgery' technique to remove basal cell cancers from 440 patients in which he obtained a 99% cure rate for primary cancers (never before treated) and a 95-96% cure rate for recurrent cancers (cancers having some other form of treatment before Mohs surgery). In its original form, the technique utilized a 20% zinc chloride fixative paste that was applied directly to the skin of the patient for fixation of tissue. Subsequently, the involved skin was surgically removed by serial excision with microscopic control of the tissue margins.

Removal of tissue was performed in layers and color coded with dyes in order orient specimens to the patient. Dr. Mohs created a unique mapping process that assisted in orienting the excised and colour-coded tissue back to the patient. Originally described, this 'chemosurgery' technique was very painful and sometimes took days to perform. Chemosurgery is no longer performed. The surgical method has now been highly refined over the last 7 decades but still uses the same principles of surgically removing a skin cancer, with microscopic guidance, so that all tissue being left behind is viewed microscopically to ensure the complete removal of the cancer. The current technique, coined 'Fresh Tissue Technique', in 1953, is performed without fixatives applied directly to the patient and with the use of local anesthetics. Tissue is now excised, processed and immediately examined in order that the entire process can be conducted in a single sitting.

In 1967, the American College of Mohs Micrographic Surgery and Cutaneous Oncology formed. The colleges mandate being to provide a means of recognition for surgeons acquiring specific certified training in the Mohs technique in addition to safeguarding the standards of the procedure. The college also functions as a regulatory and certification body for the 60 fellowship training programs (most in North America) and as a source of continuing education for more than 700 practitioners of MMS.