Mohs Surgery

Mohs Micrographic Surgery is the most advanced and effective treatment procedure for skin cancer available today. The procedure is performed by specially trained surgeons who have completed at least one additional year of fellowship training (in addition to the physician's three-year dermatology residency) under the tutelage of a Mohs College member.

Initially developed by Dr. Frederic E. Mohs, the Mohs procedure is a state-of-the-art treatment that has been continuously refined over 70 years. With the Mohs technique, physicians are able to see beyond the visible disease, to precisely identify and remove the entire tumor layer by layer while leaving the surrounding healthy tissue intact and unharmed. As the most exact and precise method of tumor removal, it minimizes the chance of re-growth and lessens the potential for scarring or disfigurement.

Because the physician is specially trained in surgery, pathology, and reconstruction, Mohs surgery has the highest success rate of all treatments for skin cancer - up to 99 percent. The Mohs technique is also the treatment of choice for cancers of the face and other sensitive areas as it relies on the accuracy of a microscopic surgical procedure to trace the edges of the cancer and ensure complete removal of all tumors down to the roots during the initial surgery.

Pre Op

When a patient arrives at our office for Mohs, any last minute questions or concerns can be addressed before getting started. A more formal consultation to discuss the operation can be scheduled in the days and weeks before surgery if a patient would prefer OR if the referring physician feels that it is necessary.

Prior to surgery, we recommend that patients get a full night’s sleep and (unless told otherwise) eat a light breakfast. The procedure is performed entirely on an outpatient basis in our office. The laboratory work involved in preparing the tissue for microscopic interpretation is labor-intensive and can take up to 1 – 2 hours or more to complete for each layer. Most patients bring a book or something to do while waiting on the results. We ask each patient to plan to spend the rest of the day with us, but some patients may be finished earlier.

If you are known to have cardiovascular disease and have been prescribed aspirin, Plavix, or Coumadin by your physician, it is not necessary to discontinue it, unless you are told otherwise. If you have not been prescribed aspirin or other blood thinners by your physician for the treatment of known cardiovascular disease, avoid aspirin for at least 7 days prior to surgery and for 2 – 3 days after surgery. All patients should try to avoid other NSAID’s (non-steroidal anti-inflammatory drugs), such as Advil/Motrin/ibuprofen, Naprosyn/Aleve/naproxen, and similar medications, and vitamin E as these medications also increase the tendency of bleeding. Plain Tylenol may be taken if pain medicine is needed. Be sure to check with your primary care physician prior to discontinuing any prescribed medications. A patient should also not drink any alcoholic beverages for two days before surgery and for one to two days afterwards.

The Procedure

The Mohs surgical process involves a repeated series of surgical excisions followed by microscopic examination of the tissue to assess if any tumor cells remain. Some tumors that appear small on clinical exam may have extensive invasion underneath normal appearing skin, resulting in a larger surgical defect than would be expected. It is therefore impossible to predict a final size until all surgery is complete. As Mohs surgery is used to treat complex skin cancers, approximately half of all treated tumors require 2 or more stages for complete excision.

Mohs micrographic surgery is distinct from routine surgical excision. With the Mohs technique, surgically removed tissue is carefully mapped, color-coded, and thoroughly examined microscopically by the surgeon on the same day of surgery. During this process, 100% of tissue margins are evaluated to ensure that the tumor is completely removed prior to repair of the skin defect. Mohs micrographic surgery therefore results in the highest cure rate for complex skin cancers while minimizing the removal of normal tissue.

Steps in detail:

  • Anesthesia

    The tumor site is locally infused with anesthesia to completely numb the tissue. General anesthesia is not required for Mohs micrographic surgery.

  • Stage I - Removal of visible tumor.

    Once the skin has been completely numbed, the tumor is gently scraped with a curette, a semi-sharp, scoop-shaped instrument. This helps define the clinical margin between tumor cells and healthy tissue. The first thin, saucer shaped "layer" of tissue is then surgically removed by the Mohs surgeon. An electric needle may be used to stop the bleeding.

  • Mapping the tumor

    Once a "layer" of tissue has been removed, a "map" or drawing of the tissue and its orientation to local landmarks (e.g. nose, cheek, etc) is made to serve as a guide to the precise location of the tumor. The tissue is labeled and color-coded to correlate with its position on the map. The tissue sections are processed and then examined by the surgeon to thoroughly evaluate for evidence of remaining cancer cells. It takes approximately 60 minutes to process, stain and examine a tissue section. During this processing period, your wound will be bandaged and you may leave the operative suite.

  • Additional stages - Ensuring all cancer cells are removed

    If any section of the tissue demonstrates cancer cells at the margin, the surgeon returns to that specific area of the tumor, as indicated by the map, and removes another thin layer of tissue only from the precise area where cancer cells were detected. The newly excised tissue is again mapped, color-coded, processed and examined for additional cancer cells. If microscopic analysis still shows evidence of disease, the process continues layer-by layer until the cancer is completely removed.This selective removal of tumor allows for preservation of much of the surrounding normal tissue. Because this systematic microscopic search reveals the roots of the skin cancer, Mohs surgery offers the highest chance for complete removal of the cancer while sparing the normal tissue. Cure rates typically exceed 99% for new cancers, and 95% for recurrent cancers.

  • Reconstruction

    Fellowship-trained Mohs surgeons are experts in the reconstruction of skin defects. Reconstruction is individualized to preserve normal function and maximize aesthetic outcome. The best method of repairing the wound following surgery is determined only after the cancer is completely removed, as the final defect cannot be predicted prior to surgery. Stitches may be used to close the wound side-to-side, or a skin graft or a flap may be designed. Sometimes, a wound may be allowed to heal naturally.

Post Operative Care

Immediately after surgery and during the recovery period, there will often be the sensation of tightness as well as soreness of the treated area. The area can also become very swollen and bruised depending on the extent of involvement. A variable degree of transient numbness of the area is generally expected due to nerve involvement, but complete and permanent loss of nerve function is rare. The incision line(s) typically improve in appearance over the first three to six months postoperatively, especially if exposure to the sun is avoided. Because the Mohs surgeon removes only the diseased tissue and as little healthy tissue as possible, the extent of scarring (which normally occurs after any surgery) is kept to a minimum.

It is important that patients take every precaution following Mohs micrographic surgery for skin cancer. In particular, adhering to a strict sun avoidance program helps to reduce the risk of further skin cancers. It is also important that patients be carefully monitored on a regular basis by their primary dermatologist after surgery. Research has shown that if there is a recurrence of skin cancer, it usually occurs within the first year. Furthermore, a significant percentage of patients who develop one skin cancer will get another within the next five years. Prevention and early detection are key.