Mohs Micrographic Surgery is an advanced treatment for skin cancer that offers the highest cure rate – even if the skin cancer has been previously treated by another procedure. Mohs Micrographic Surgery is a state-of-the-art treatment in which the physician serves as surgeon, pathologist and reconstructive surgeon. It relies on the ability of a microscope to trace out and ensure removal of the skin cancer’s roots. This procedure allows physicians to see beyond the visible disease and to precisely identify and remove the entire tumor, leaving healthy tissue intact and unharmed. Mohs surgery is most often used to treat two of the most common forms of skin cancer: basal cell carcinoma and squamous cell carcinoma, however it is also an effective treatment for other types of skin cancer.
Clinical studies have shown that the cure rate for Mohs Micrographic Surgery is the highest of all treatments for previously untreated basal cell carcinoma – 99 percent – and 95 percent for recurrent basal cell carcinomas. As the most exact and precise method of tumor removal, this procedure minimizes the chance of recurrence and decreases the potential for scarring or disfigurement. As such, Mohs surgery offers the highest potential for complete removal of the cancer, while sparing the surrounding healthy tissue.
Common treatment procedures such as curettage, and electrodesiccation, cryosurgery, and radiation therapy often prove less effective because they destroy the tissue and leave no specimen for pathological examination. Standard surgical excision relies on the human eye and examines only a fraction of the actual surgical margins for cancer, whereas Mohs surgery evaluates 100 percent of the surgical margins. In an effort to preserve healthy tissue, too little too much healthy tissue, resulting in unnecessary scarring.
Some tumors often do not respond well to common treatments, including those tumors greater than two centimeters in diameter, those in difficult locations and those complicated by prior treatment. Removing a recurrent skin cancer is more complicated because scar tissue may hide cancerous cells. In these cases Mohs surgery is the most appropriate treatment.
The Mohs process includes a specific sequence of surgery and pathological investigation. Mohs surgeons examine the removed tissue for evidence of cancer cells. Once the visible tumor is removed, Mohs surgeons trace out the paths of the tumor using two key tools:
- a map of the surgical site;
- a microscope.
Once the obvious tumor is removed, Mohs surgeons:
- remove an additional, thin layer of tissue from the tumor site;
- create a “map” or drawing of the removed tissue to be used as a guide to the precise location of any remaining cancer cells;
- microscopically examine the removed tissue thoroughly to check for evidence of remaining cancer cells.
If any of the sections contain cancer cells, Mohs surgeons:
- return to the specific area of residual tumor as indicated by the map;
- remove another thin layer of tissue only from the specific area where cancer cells were detected;
microscopically examine the newly removed tissue for additional cancer cells.
If microscopic analysis still shows evidence of disease, the process continues, layer-by-layer, until the cancer is completely removed.
Mohs Micrographic Surgery is used primarily to treat basal and squamous cell carcinomas, but can also be used to treat less common tumors.
Mohs surgery is indicated when:
- the cancer is in a difficult area where it is important to preserve healthy tissue for maximum functional and cosmetic result, such as eyelids, nose, ears, lips, fingers, toes and genitals;
- the cancer was treated previously and recurred;
- the cancer is large;
- the edges of the cancer cannot be clearly defined;
- the cancer grows rapidly or uncontrollably;
- scar tissue exists in the area of the cancer.
The best method of managing the wound resulting from surgery is determined after the cancer is completely removed. Once the final defect is known, management is individualized to achieve the best results and to preserve functional capabilities and maximize aesthetics. The Mohs surgeon is also trained in reconstructive procedures and usually will perform the reconstructive procedure necessary to repair the wound. A small wound may be allowed to heal on its own, or the wound may be closed with sutures, a skin graft or a flap. On some occasions another surgical specialist may complete the reconstruction as part of a team approach.
In addition to its high cure rate, Mohs Micrographic Surgery also has been shown to be cost effective. In a study of costs of various types of skin cancer removal, the Mohs process was found to be comparable to the cost of other procedures, such as electrodesiccation and curettage, cryosurgery, excision and radiation therapy.
In addition, Mohs Micrographic Surgery has other advantages:
- Because it preserves the maximum amount of normal skin, Mohs surgery often results in smaller scars.
- With its high cure rate, Mohs surgery minimizes the risk of recurrence and eliminates the need for more complicated surgery, which may be necessary if the cancer recurs.
- Because the Mohs procedure is performed in the surgeon’s office and pathological examination of the tissue is conducted immediately, the entire process can often be completed in a single day.