Expert Dermatology Services

Mohs Surgery

Mohs Micgrographic Surgery for skin cancer offers a 99.9% cure rate for most non-melanoma skin cancers. This tissue-sparing procedure is performed under local anesthesia. The skin cancer is removed with a small margin and is followed by immediate microscopic examination of the entire tissue specimen margin by frozen tissue processing techniques. The patient waits for the results, and the tumor is oriented so that if further resection is needed, only the area with the residual cancer is removed. The entire process typically takes 2-4 hours. Dr. Joanna Chan serves as the fellowship-trained 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. Your cancer is marked, and the location is confirmed with a mirror.
2. The skin is numbed with a local anesthetic. Additional markings on the skin provide orientation, followed by surgical removal of a 1-2 mm margin around biopsy site, containing the tumor in the shape of a pie.
3. The first pie-shaped “layer” of skin is color-coded and divided into slices that are mapped onto paper, using the same orientation that corresponds to the markings on the patient’s skin.
4. The laboratory technician expertly freezes the tissue, sections the specimen horizontally into tissue paper thin slices that are placed onto glass slides and stained in the lab. This technique allows 100% visualization of the epidermis such that the entire border of the tissue or the “pie crust” is examined.
5. The slides are examined by your Mohs Surgeon to determine if any tumor cells remain. If any cancer remains on one edge, then only that section containing the cancer is resected further. The process of removal, tissue processing, and microscopic examination continues until the skin cancer is removed completely.
6. Once clear of cancer, the skin defect is repaired under local anesthesia utilizing advanced reconstruction techniques.

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 the 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. Stop taking any blood thinners prior to surgery. Aspirin or Aspirin-containing products block platelets for 10 days, so please stop any optional aspirin 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). {{{{{{Link to Blood thinner list here}}}}}}} Please consult your prescribing physician prior to stopping any aspirin, Plavix, Eliquis, Xarelto, Coumadin, etc. (primary care doctor or cardiologist).
2. Antibiotics prior to surgery may be needed if you need to take antibiotic prophylaxis before surgery or dental procedures. Please 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 several days in advance of your surgery date, so that a prescription can be provided to your pharmacy. We recommend antibiotic prophylaxis for any tumors near mucosal surfaces (lips, eyes, nose), ears, scalp, hands or lower extremities, as these are prone to infection. Take these antibiotics with food to avoid nausea.
3. A driver will be needed, 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. If you require anxiety medication due to claustrophobia or a history of panic attacks, a driver will also be required.
4. Shower or bathe on the morning of surgery, and wash your hair, as you will not be able to shower again for 24 hours.
5. Eat a hearty breakfast or lunch on the day of surgery. You may bring your lunch or snacks, and we have refrigerator space available for you. Expect to be here for 2-4 hours and do not schedule any important functions for the rest of the day.
6. Please wear comfortable clothing that you do not mind getting dirty. Make sure that your shirt buttons in the front or can easily slip over your head without disrupting a bandage. Do not wear one-piece outfits unless the lesion is on the leg, and the cancer is easily exposed with this type of clothing.
7. If the cancer is on the lower legs, please bring compression hose (20/30 mmHg) and loose-fitting shoes, if a pressure bandage is required for the foot. These areas are especially prone to infection so please remember to take your antibiotics.
8. Do not wear any makeup if the skin cancer is on your face. Please shave any hairy areas around the tumor, as you will not be albe to shave this area until sutures are removed.
9. Take all of your routine medications (especially take your blood pressure medication), as you normally would EXCEPT any of your medications that we have told you to stop.
10. 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 and allows you to avoid a no-show charge that must be paid to the technician.

Please ice the surgical area over the bandage for 5-10 minutes every hour following surgery for the first two days. An ice pack or frozen peas works best. This reduces pain, swelling, bruising, and the risk of bleeding. Do not schedule any important meetings, weddings, or reunions during the week after surgery as you will likely have a bruise. Please relax and recover from surgery during the remainder of the day. Do not exercise or elevate your blood pressure for 48 hours.

Expect swelling and bruising around the surgical site. If the cancer is on the scalp or face, you may experience a black eye that can last about 1-2 weeks. Keep the area elevated by sleeping on two pillows.

Surgery on the forehead, cheek, or eyelid may result in black eye(s) that can last about a week.

Please wear compression stockings (20/30 mmHg) for any surgery located on the lower leg. We can prescribe these, or they can be purchased online. Do not stretch the area until sutures are removed (1-2 week, depending on the site). Avoid heavy lifting, weight-bearing exercise for the location involved, or any kind of activity or motion that can stretch the area. You can shower 24 hours after surgery but do not scrub the area. Swimming is not allowed until after the sutures are removed.

Scar appearance can be improved by using silicone gel, which is available over the counter or medical grade silicone can be purchased at our office. Please start these one week after sutures are removed, along with firm massage for 10 minutes, twice a day. Strict sun avoidance and reapplication of physical blocker sunscreens every 2 hours, if the area is not covered.

Schedule your full body skin examination every 6 months with a board-certified dermatolgoist.
Please refer to the following handouts for more information:
1. Blood Thinners to Avoid
2. Mohs Micrographic Surgery Patient Brochure
3. Wound Care Instructions (Steri-Strips)