Skin Cancer + Mohs Surgery

Mohs Surgery for skin cancer combines surgical excision under local anesthesia with immediate microscopic examination of the entire tissue specimen margin by frozen tissue processing techniques, while the patient waits for the results. Your physician serves as the Mohs surgeon and pathologist, examining 100% of the tissue margin to ensure clearance of the cancer while minimizing the sacrifice of normal skin.

Mohs Surgery Procedure

  1. The skin is numbed with a local anesthetic, marking the skin to create a map, followed by surgical removal of a thin layer of skin (1-2 mm margin around biopsy site), containing the tumor in the shape of a pie.
  2. The pie-like specimen is divided into slices that are mapped and color-coded onto a paper map in the same orientation that corresponds to the patient’s skin.
  3. Our laboratory staff freezes the tissue, sections into tissue paper thin slices that are placed onto glass slides and stained in our Mohs lab. The tissue is oriented onto the slide, so that the border of the tissue or the “pie crust” is examined.
  4. The slides are examined by your Mohs Surgeon to determine if any tumor cells are left behind. If the tumor is removed completely, the skin defect is ready to be repaired. If the specimen has residual tumor, steps 1 through 4 are repeated until the skin is clear of tumor (see diagram).

Mohs Micrographic Surgery vs. Standard Excision

The Mohs Micrographic Surgery technique differs from standard excision in that less normal tissue is removed initially (1-2 mm margin), and 100% of the tissue edge is processed to control the margin microscopically using an iterative technique. By reducing the amount of normal skin removed, this minimizes size of the defect, making it easier to repair the defect, thus resulting in a smaller scar. Reconstruction usually occurs immediately after removal.

Standard excision usually requires 4-5 mm margins, and the tissue is processed using sections cut up and down like a bread-loaf, such that the pathologist only examines 1% of the margin. Even with “clear margins” as assessed by the pathologist, the curative rate with standard excision is 94-95% (approximately 1 in 20 will recur) compared to 99.9% cure with Mohs Micrographic Surgery.

Mohs surgery is indicated for recurrent skin cancers, tumors of the head/face & neck, large and ill-defined tumors off the face, aggressive pathology (micronodular, infiltrative, morpheaform tumors), areas of prior radiation, immune compromised patients (e.g., lymphoma patients), and cancers occurring in areas with limited tissue mobility (e.g, hands, shins).

Because the tissue is processed in the lab, and multiple stages may be required to clear the tumor, patients are advised that the procedure may last 2-4 hours, and in rare instances longer. We advise patients to eat a good breakfast or lunch prior to the procedure, and to bring reading material or something to occupy their time while waiting for results.

How To Prepare For Your Surgery

  1. Do not take any blood thinners prior to surgery. Stop Aspirin or Aspirin-containing products for at least 2 weeks prior to your surgery. The most common blood thinners are fish oil, vitamin E, ibuprofen or other anti-inflammatory medications (NSAID’s). Please see entire list. Stop Aspirin, Plavix, and Coumadin only if your Cardiologist approves.
  2. If you need to take antibiotic prophylaxis before surgery or dental procedures, take your first dose 1 hour before coming to the office for your Mohs surgery. If you do not have a prescription at home, please notify us at least 3 days in advance of your surgery date so that a pharmacy can be called. We recommend antibiotic prophylaxis for any tumors near mucosal surfaces, or near mouth, eyes, ears, or lower extremities as these are prone to infection.
  3. If your skin cancer is located in the center of your face, eyelid, or eyebrow area where a bandage will block your vision or impact your ability to wear glasses, please have someone available to drive you to and from the office.
  4. Eat a normal breakfast or lunch on the day of surgery. If you wish to bring your own lunch or snacks, we have refrigerator space available for you.
  5. Please wear comfortable clothing that you do not mind getting dirty. Make sure that your shirt buttons in the front and does not slip over your head unless you wish to wear a paper gown. Do not wear one-piece outfits.
  6. Please take a shower and wash your hair on the morning of the day of surgery. You will not be able to shower for 24 hours following surgery. Do not apply makeup (if the skin cancer is on your face), perfume, aftershave, or cologne. Shave any hairy areas around the tumor.
  7. Take all of your routine medications, as you normally would EXCEPT any of your medications that we have told you to stop.
  8. If you are unable to keep the scheduled appointment for surgery, please contact our office at least 48 hours in advance to reschedule your surgery appointment. This allows us to schedule other patients waiting to take your slot.

Activity Level Following Surgery

Aim to spend the first day following surgery relaxing and recovering from surgery. Do not elevate your blood pressure for 48 hours. Expect the area around the surgical site to bruise, which can last 1-2 weeks. Keep the area elevated (sleep on a few pillows if tumor is on the head). Ice the area using frozen peas or ice packs for 5-10 minutes each hour while awake for the first 1-2 days to minimize pain, swelling, and bruising. Surgery on the forehead, cheek, or eyelid may result in black eye(s) that can last about a week. If the surgery was on the lower leg, we recommend wearing compression stockings immediately after surgery, which can be prescribed if you do not own any. Heavy lifting and exercise are not allowed until after the sutures are removed. You can shower 24 hours after surgery. Swimming is not allowed until after the sutures are removed.

Please refer to the following handouts for more information:

  1. Blood Thinners to Avoid
  2. Mohs Micrographic Surgery
  3. What to Expect
  4. Wound Care Instructions

If you’d like to learn more about skin cancer procedures, please fill out the form on this page or call (562) 997-1144.