Mohs Surgery

What are advantages of Mohs surgery?

By microscopically pinpointing areas involved with cancer and selectively removing only these areas, normal tissue is preserved to the greatest extent possible. This procedure results in the smallest possible skin tissue defect and therefore, the smallest possible scar. In addition, the cure rates for skin cancers treated with Mohs technique are very high, often 97-99%, even if other forms of treatment have failed. While the Mohs technique gives the best possible chance of a cure, it is not a 100% guaranteed cure.

Duration of surgery

The removal of each layer of tissue takes approximately one hour. Only 20 to 30 minutes of that time is spent in the actual surgical procedure. The remaining time is required for slide preparation and interpretation. Removal of two or three layers of tissue (called ‘stages’) is usually required to complete the surgery. Therefore, by beginning early in the morning, Mohs surgery is generally completed in one day. Rarely, a tumor may be extensive enough to necessitate continuing surgery a second day, or requiring the repair to be performed a subsequent day.

How do I prepare for the surgery day?

We prefer that wounds be kept dry after the completion of surgery. Therefore, we recommend a thorough bath or shower (including washing your hair) on the eve or morning of surgery. Shave the surrounding hair to avoid pulling by the bandage. The best preparation for Mohs surgery is a good night’s rest followed by eating breakfast. If you are taking any medications, take them as usual, unless we direct otherwise. Bring complete list of medications on the day of surgery. Because you can expect to be with us for at least half of the day, it is wise to bring something to read. Please do not make other plans or appointments for the day. We request that you stop taking any aspirin, NSAID’s (like Advil, Motrin or Aleve), fish oil, and vitamin E at least 10 days before your surgery, since they may interfere with the normal blood clotting mechanism and cause excessive bleeding. If you are taking any over-the-counter medications, please check with your pharmacist to see if they contain any aspirin-derivatives or blood-thinning properties.

The removal of each layer of tissue takes approximately one hour. Only 20 to 30 minutes of that time is spent in the actual surgical procedure. The remaining time is required for slide preparation and interpretation. Removal of two or three layers of tissue (called ‘stages’) is usually required to complete the surgery. Therefore, by beginning early in the morning, Mohs surgery is generally completed in one day. Rarely, a tumor may be extensive enough to necessitate continuing surgery a second day, or requiring the repair to be performed a subsequent day.

What happens on the day of surgery?

Appointments for surgery are usually scheduled early in the day to allow us to continue throughout the entire day if necessary. One of our staff will prepare you for surgery by checking your medications and medical history and obtaining your signed informed consent for the surgery. The area around your skin cancer will be anesthetized (numbed) with a local anesthetic. This should feel like the anesthetic applied during skin biopsy and and may uncomfortable for a few seconds.
Usually this is the only pain you will experience during the procedure.

Once the area is numbed, a layer of tissue will be removed and the bleeding controlled. The layer of removed tissue will be carefully handled by your surgeon, mapped and color-coded, and sent to the technician to be processed onto microscope slides. A pressure dressing will be placed over your surgical wound, and you will then be escorted back to the waiting room while the tissue is processed for microscopic examination by the surgeon. On average, it takes an hour for the slides to be prepared and studied. During this time you may wait in the waiting room, read your book or magazine, or visit with friends. Most Mohs surgery cases are completed in two or three stages. Each stage involves the removal and microscopic examination of your skin for cancer. Once we are sure that we have
totally removed your skin cancer, we will discuss with you our recommendations for dealing with your surgical wound. Most repairs are performed on the same day, but a delayed repair may be favorable if a skin graft is needed, since this will allow the wound to shrink.

What happens after tumor removal?

After Mohs surgery, you will be left with a surgical wound. This wound will be reconstructed in one of several ways. To achieve an optimal functional and cosmetic outcome, and to speed wound healing, a skin flap or graft may be required to reconstruct the wound. This may be performed on the day of surgery or may be delayed by a day or longer. Delayed reconstruction does not significantly increase the risk of infection or poor healing. Your options for reconstruction will be discussed after your skin cancer has been removed.

What happens after the skin heals?

Initially, the wound will feel tight, but should relax within several months. Occasional itching or twinges of pain may occur. A scar may remain raised and pink for many months, but should finally become flat and pale in a year or so. Occasionally, scars become thick, raised red scars known as hypertrophic scars or keloids. This can be prevented by using silicone scar gel. Persistently red and raised scars should be treated immediately. Please contact our office if this type of scarring persists for over two months. Patients frequently experience itching after the wounds have healed because the new skin that covers the wounds does not have as many oil glands as previously existed. Aquaphor ointment can help relieve itching. Sunscreen should be applied every 2 hours.

How often do I return for follow-up?

If the wound has been reconstructed, you will be asked to return for suture removal to judge wound healing. After the wound has healed, we recommend that you have a complete skin examination every 6 to 12 months by a dermatologist. If there is a recurrence of the skin cancer after Mohs surgery, it should be inspected at once and treated promptly. Also, should you notice if there are any other suspicious areas on your skin, it is best to check with your dermatologist to see if a biopsy is indicated.

Will I develop more skin cancer?

Studies have shown that once you develop a skin cancer, there is a high possibility that you will develop others in the years ahead (nearly 50% in the next 5 years). This risk is increased if you have any lymphoma, leukemia, or immunosuppression. The damage which your skin has already received from the sun cannot be reversed. Therefore, those who have had one skin cancer should be examined at least once a year by a dermatologist. We recommend reapplying medical grade sunscreen every 2 hours while outdoors to protect any skin exposed to the sun.

If the wound has been reconstructed, you will be asked to return for suture removal to judge wound healing. After the wound has healed, we recommend that you have a complete skin examination every 6 to 12 months by a dermatologist. If there is a recurrence of the skin cancer after Mohs surgery, it should be inspected at once and treated promptly. Also, should you notice if there are any other suspicious areas on your skin, it is best to check with your dermatologist to see if a biopsy is indicated.

What can I expect after the surgery?

• Pain: Ice the area every hour while awake for 5-10 minutes around the bandage. Extra-strength Tylenol (500 mg tabs, take 2 tabs every 4 hours, up to 8 tabs a day) should reduce the pain. Narcotic drugs are rarely needed and require special paper prescriptions. Ibuprofen (600-800 mg) taken after a meal can help.
• Bleeding: The anesthetic mixed with a small amount of blood is normal to see on the pressure bandage. Bleeding that soaks the entire bandage rarely occurs. Activity will cause more bruising. Highest risk is the first 48 hours, so take it easy and avoid unnecessary blood thinners. If you notice a completely blood-soaked bandage, lie down & apply constant & very firm pressure with a gauze pad. Set a timer, and do not lift up or relieve the pressure at all
  for 20 minutes. Reset the timer if you peek or let go of pressure. If bleeding persists after continued pressure for 20 minutes (timed), call our office, or go to the nearest emergency room.
• Restrictions: Depending on the size of the wound and the location of the lesion, we recommend restricted physical activity for 2 days to 2 weeks. Details will be discussed with you after the surgery.
• Scarring: Scars always result from skin surgery. The scar is minimized if the defect after cancer removal is small. This is one of the major advantages of Mohs surgery — the cancer is removed leaving the smallest defect possible. A second procedure to reconstruct the wound often improves the cosmetic outcome by placing the scar lines in natural grooves in the skin.
• Numbness: The area surrounding your scar will be numb from the local anesthesia. After the anesthesia wears off, the numbness will gradually return to normal. Some areas may persist for several months until tiny nerve fibers grow back into the area. The skin sensation then gradually returns to normal.
• Swelling and Bruising: Swelling & bruising (4-7 days) are to be expected, especially if the wound is near the eyes. Decrease bruising risk by sleeping with head elevated and applying ice around the bandage. Arnica pellets or cream can be applied to reduce bruising.
• Redness: It is normal for a small red area to develop around the wound. If this redness does not improve in two days, or if the wound smells foul or begins to drain pus, you should notify our office immediately. Itching & redness can develop where adhesive tape has been applied, or if polysporin & neosporin are used. Ask your pharmacist for a non-allergenic paper tape and tell us on your return. Scars can be red initially, fading over a year.

Mohs surgery unit

The Mohs Surgery Unit consists of a team of trained physicians, nurses & technicians. Dr. Joanna Chan is specialty fellowship trained in this technique and is a
member of the American College of Mohs Surgery.

College: Harvard University
M.D.: Stanford School of Medicine
Residency: UT Southwestern Dallas
Fellowship: California Skin Institute

Dr. Chan speaks Spanish and Chinese & has a special interest in treating patients with skin of color. She has performed thousands of Mohs Micrographic Surgery cases and is an expert in the early diagnosis and complex management of skin cancers, with over a decade of experience performing reconstruction.

Reminders before surgery

1. Eat a hearty breakfast, then take all of your morning medications (except blood thinners). Bring any medications that you will need for the entire day.
2. To prevent excessive bleeding, stop taking the following at least 10 days before surgery: Aspirin, Non- steroidal anti-inflammatory agents (Voltaren, Relafen, Ibuprofen, Naprosyn), vitamin E & fish oil. Please ask us for a complete list as many vitamins cause bleeding.
3. If your doctor prescribed blood-thinning medications such as Coumadin (warfarin), Plavix, Eliquis, Aspirin (e.g., for stent, stroke), etc., ask your prescribing physician before stopping these medications. If you are on Coumadin, please have an INR blood test checked within 1-2 weeks of your surgery date (target: 2 – 2.5)
4. Do not drink alcoholic beverages (including wine and beer) for three days before and after surgery. Alcohol can cause excessive bleeding. To improve wound healing, stop smoking before and after surgery.
5. Please let our staff know before the day of surgery if you routinely take antibiotics before dental procedures or have any of the following medical conditions: Heart Murmur, Artificial Heart Valves or Joints, implanted devices such as a Deep Brain Stimulator, Mitral Valve Prolapse, History of Rheumatic Fever.
6. Prepare to stay all day, and do not make any other plans. Please do not bring any small children. Bring a driver if you need light sedation, and arrive 1 hour early. Please call our office with any further questions that you may have. We can send you written materials to review.