Mohs Surgery vs. Excision: Comparing the Uses, Benefits, and Risks of Commonly Performed Skin Cancer Treatments

Skin cancer is the most frequently diagnosed malignancy in the US. This condition is also one of the most challenging to treat, as cosmetic preservation of the affected area is as important as eliminating the cancer cells. That is why this problem is best left in the hands of a licensed dermatologic surgery specialist.

Mohs surgery is the most highly recommended skin cancer treatment because it addresses the medical and cosmetic aspects of the condition. In our practice, many patients ask if Mohs surgery and excision are the same. Though both treatments mechanically take out cancerous tissue, they use different techniques and impact the condition’s progress differently.

This article compares Mohs surgery and surgical excision to guide patients when choosing which skin cancer treatment option is best for them.

What Is Mohs Surgery?

Mohs micrographic surgery, or Mohs surgery for short, is a tissue-sparing method of treating skin cancer. A Mohs surgeon is a board-certified dermatologist highly trained in performing this specialized procedure. 

During a Mohs operation, we remove the tumor tissue layer by layer, microscopically examining each layer for the presence of cancer cells. We repeat the process until a thin, cancer-free piece of tissue is obtained. The procedure can take hours, but the patient will know right away when we’ve completely taken the lesion out. Additionally, most of the surrounding healthy tissue is spared, so the area will not change much in appearance or function after the session.

When Should Mohs Surgery Be Used?

Mohs surgery is recommended for most skin cancer types, whether or not they have a high recurrence risk. Patients with particular health needs, such as those with a history of cancer or immunosuppression, may also benefit from a Mohs procedure.

Mohs surgery is highly useful in the following situations:

• The tumor location is vital to daily activities or a person’s appearance.
• The skin cancer has not responded well to previous treatments.
• The lesion is large, i.e., diameter greater than 2 cm.
• The lesion is not amenable to wide local excision. 

Mohs micrographic surgery’s cure rates have made it the standard of care for basal cell and squamous cell skin cancer. That means tumor recurrence is unlikely after the treatment. Additionally, Mohs procedures are increasingly becoming more valuable in removing rare skin cancer types like melanoma.

What Types of Skin Cancer Is Mohs Surgery Used For?

Mohs procedures are highly effective in removing common and rare skin cancer types. They include the following:

Basal Cell Carcinoma

Basal cell carcinoma is the most prevalent skin cancer type. Most cases are related to excessive UV light exposure. Fair-complexioned individuals are most frequently affected, although patients of color overly exposed to the sun may also develop the condition.

Basal cell cancer may start as a nonhealing lesion that ulcerates and bleeds easily. It may be dome-shaped or have a rolled border. The lesion usually grows in a sun-exposed area but can also appear in other locations. Pigmentation varies by subtype.

Mohs treatment has a cure rate of up to 99% in individuals with basal cell carcinoma. This type of skin cancer is locally aggressive but rarely spreads remotely or causes significant illness. Early treatment is recommended to prevent disfigurement and other complications.

Squamous Cell Carcinoma

Squamous cell carcinoma is the second most common skin cancer type in immunocompetent patients and the most common type in immunocompromised individuals. Most cases are due to excessive UV exposure, though the following factors have also been implicated in the development of this condition:

• X-rays and other strong radiation types
• Chemical carcinogens like arsenic
• Genetics
• Immunosuppression
• Chemotherapeutic drugs
• Chronic skin inflammation
• Infection with high-risk human papillomavirus (wart) strains

The typical squamous cell carcinoma lesion is a slow-growing, firm, skin-colored or reddish mass, usually in a UV-exposed region. Skin thickening, scaliness, ulceration, and bleeding after minimal trauma are accompanying symptoms. However, there are many squamous cell carcinoma types, and their presentations are highly varied.

The risk of metastatic spread of a squamous cell tumor is low, so most cases are detected early. Mohs surgery has a cure rate of up to 99% in patients with this condition. However, severe complications are frequent when this illness is detected late.

Melanoma

Melanoma is an aggressive skin cancer type that affects the melanocyte, the pigment-forming cell of the skin. This condition is rare, but it causes most skin cancer fatalities. Risk factors include UV exposure, genetics, and immunosuppression.

Melanoma starts as a mole-like lesion that later develops unusual features, such as abnormal color and asymmetry. Growth and metastatic spread can occur within months. In our practice, we advise patients to perform a self-skin examination regularly to ensure that conditions like melanoma are caught and treated early. You may read my previous article comparing melanoma to common moles to learn more about early skin cancer detection at home.

Mohs surgery has a cure rate as high as 98% in early melanoma. Larger tumors are more difficult to remove by any surgical technique and typically require systemic, more aggressive therapy. That is why early detection is vital. Individuals treated for late-stage melanoma are highly at risk for recurrence, even decades later. 

Premalignant lesions like actinic keratosis and atypical moles are often confused with skin cancer. A biopsy helps distinguish between these conditions. Mohs surgery is usually not recommended for benign tumors, as most of them respond to topical medications and minimally invasive procedures like laser therapy. However, we do remind our patients that the sooner they treat suspicious lesions, the better the long-term results.

What Are the Benefits of Mohs Cancer Surgery?

The following are the benefits of Mohs surgery:

• High cure rates: Mohs surgery cure rates reach as high as 99% for basal cell and squamous cell carcinoma and 98% for early melanoma. That means this treatment has a recurrence rate of only 2% or less for these lesions. Other skin cancer types also respond well to Mohs procedures.
• Good cosmetic outcomes: This tissue-sparing surgical technique does not significantly change the appearance of the treated area—other than removing the tumor, of course.
• Excellent functional outcomes: Mohs surgery leaves as much normal tissue as possible, so the treated area remains functionally intact after the session.
• Immediate result: Mohs surgeons like myself are trained in both the surgical and histopathological aspects of the procedure. We examine the tissue samples for cancer cells as soon as we take them out. Patients don’t need to wait days for histopathology results. Once we close the surgical site, they’ll know right away that they’re cancer-free.

• Useful for various skin cancer types: Mohs surgery’s high success rates in various low- and high-risk skin cancer types make it an indispensable tool for skin cancer specialists.
• Outpatient procedure: Mohs treatment is performed under local anesthesia, sparing patients from the potential complications of general anesthesia. You’ll remain awake during and after the session.
• Rarity of complications: Severe side effects are rare when a highly experienced Mohs specialist does the procedure. The physician performs the treatment guided by a thorough medical examination and under strict surgical standards.

These advantages make Mohs micrographic surgery the best skin cancer treatment.

What Can You Expect When Undergoing a Mohs Procedure?

When a patient comes to me with a suspicious skin lesion, my foremost goal is to determine whether or not the lesion is malignant. I give the patient a complete medical exam before making a treatment plan. I order a biopsy to confirm the diagnosis and include other lab tests if needed.

If Mohs surgery is a patient’s best treatment option, the BHSkin Dermatology staff sets them up for an appointment right away. Some may need medical clearance from their primary care providers ahead of their session. Pretreatment preparation includes avoidance of alcohol, smoking, and blood thinners starting days before their appointment.

Patients must keep the treatment area clean before they come in for surgery. At the start of the session, I clean the area with an antiseptic, drape the surrounding regions, and inject local anesthesia. The numbing medication usually works within 30 minutes, though I still test the site for sensation before making my first incision.

Once the local anesthesia takes effect, I start cutting away at the tumor. I take thin incisions, making sure to remove skin cancer cells without damaging healthy tissue. Then, I close up the site temporarily and microscopically examine the cut-out parts for the presence of cancerous cells. My staff will ensure you are comfortable while waiting for me to complete my assessment.

I repeat the process until I get a thin margin without residual tumor tissue. When it’s all done, I close up the surgical site and clean it up before sending you home. The entire session usually takes several hours to complete. 

What Are the Dos and Dont’s After Mohs Surgery?

I have previously written about the Mohs surgery recovery process in detail. However, below is the gist of the aftercare regimen:

• Leave the pressure dressing on for 24-48 hours.
• Gently clean the wound with mild soap and water when taking a bath.
• Apply an antiseptic solution before bandaging the wound again.
• Elevate the area when you sleep.
• Protect the site from sun exposure, harsh chemicals, and dirt.
• Avoid picking at the surgical site.
• Apply silicone gel to prevent scarring.
• Take oral antibiotics and other medications as prescribed.

Good aftercare ensures a speedy recovery and excellent cosmetic results. Healing may take 1-2 weeks for most people. Factors like advanced age and immune function can prolong the post-treatment period.

Does Mohs Surgery Have Side Effects?

Every medical procedure has potential side effects. The most common ones for Mohs surgery are mild and transient pain, redness, and swelling due to natural inflammation.

Complications are rare as Mohs procedures are performed in a sterile environment by a highly trained skin surgical specialist. They include the following:

• Wound infection
• Suture reaction if sutures are used to close the wound
• Bleeding or bruising
• Tenderness or pain in the surgical site
• Nerve damage that may lead to permanent weakness of the affected area
• Scarring or deformity of the surgical site
• Permanent hair loss in the treated area
• Pigmentation changes over the surgical site

Two things can prevent these complications: working with a highly experienced, board-certified Mohs surgeon and strict adherence to the pre- and post-treatment care instructions. In my practice, patients are happy with the results they get after Mohs surgery.

What Is Surgical Excision?

Surgical excision is the traditional way of removing any cancer type. Even surgeons who do not specialize in skin cancer surgery can perform this procedure. The physician takes the entire tumor out along with a wide margin of healthy skin tissue. The excised tissue is not examined on-site for cancer cells but sent to a pathology lab for analysis. It can take days before the results come out, and even then, there’s no guarantee that the entire lesion has been removed.

Who Performs Surgical Excision?

As previously mentioned, traditional excision procedures can be performed by surgeons not specializing in skin cancer surgery. They include:

• General surgeons: doctors who perform procedures in most parts of the body
• Orthopedic surgeons: physicians who specialize in the musculoskeletal system and lesions of the extremities
• Surgical oncologists: surgeons who specialize in the removal of any malignant tumor
• Plastic surgeons: doctors who can remove tumors by standard excision and reconstruct significant defects  

A board-certified dermatologist may also perform a simple skin tumor excision, but only if Mohs surgery is absolutely not an option. Not all dermatology clinics offer this procedure due to personnel or equipment limitations, and some skin cancers are better removed by simple excision.

What Is Surgical Excision Used For?

Simple excision can treat both benign and malignant lesions, including the ones that Mohs procedures can remove. However, dermatologic surgeons will only recommend wide local excision for skin cancer if Mohs surgery is not an option or if the patient chooses to have a more affordable skin cancer treatment. Traditional excision’s cure rates are not as high as Mohs surgery’s.

What Are the Benefits of Wide Local Excision?

The following are the benefits of traditional excision:

• Shorter procedure time: Excisional surgery is relatively quicker than Mohs treatment because it is not interrupted by tumor tissue examination.
• Treats various lesions: Wide local excision may remove both benign and malignant skin growths. This procedure is useful for removing large moles that appear benign but must be proven so by histopathology.
• Does not require a specialized surgeon: As earlier stated, various surgeons can perform simple excision. The procedure is available in more geographic locations than Mohs surgery.
• Standard of care for deeper melanoma lesions: Wide local excision remains the standard of care for larger melanomatous tumors due to the current technical limitations of Mohs surgery in treating the condition. However, melanoma excision is associated with complications like poor healing, scarring, and functional impairment.

As in Mohs surgery, wide local excision of a skin tumor is typically performed under local anesthesia. The procedure spares you from the possible complications of sedatives and general anesthesia.

What Are the Risks Associated with Excision Surgery?

The following are the potential risks of wide local excision of a skin malignancy:

• Scarring: Wide local excision tends to produce large scars because it requires cutting out a large portion of the surrounding tissue. Disfigurement and dysfunction are the worst possible complications of this technique.
• Risk of incomplete cancerous tissue removal: Without an in-procedure microscopic examination of the excised tissue, the surgeon is usually unsure if the entire tumor has been removed, even after cutting out a wide margin. 
• Higher recurrence rate: The cure rates of simple excision are 87-96% for basal cell carcinoma, 92-95% for squamous cell carcinoma, and 83-85% for early-stage melanoma. Skin cancer recurrence is, thus, more likely after this procedure.
• Possible need for post-surgical systemic therapy: Patients may be prescribed some form of systemic treatment if the histopath exam reveals that the tumor has not been entirely removed. Systemic therapy is usually associated with serious complications, such as severe immunosuppression and susceptibility to other cancer types.
• Prolonged healing time: The surgical wounds created by this technique are larger, thus requiring more time to heal.

Traditional excision may also lead to infection, bleeding, nerve damage, and allergic reactions. You may avoid these complications by working with a highly experienced provider and strict adherence to the pre- and post-treatment regimens. Alternatively, have a Mohs surgery done if your dermatologist recommends it.

What Are the Advantages of Mohs Surgery Over Wide Local Excision?

Mohs surgery is highly recommended for various skin cancer types because of the following advantages:

• Higher cure rates
• Better cosmetic and functional outcomes
• Faster recovery
• Lower risk of pain, scarring, poor wound healing, and other complications
• Immediate results, as patients know that the tumor has been eliminated right after the procedure

These upsides make Mohs surgery superior to other skin cancer treatment options. 

What Are the Advantages of Wide Local Excision Over Mohs Surgery?

Although Mohs surgery is an effective method for treating skin cancer, there are several drawbacks associated with the procedure. They include:

• Technical limitations when treating large melanoma lesions
• Longer procedure time
• Requires special training
• Unavailable in some territories
• High upfront costs, although the rarity of recurrence after Mohs surgery makes it more cost-effective than simple excision

In my practice, I always work with my patients to come up with the treatment most suitable for their needs. The best form of skin cancer therapy is the one that gets done and gets done right.

Mohs Surgery vs. Excision: Which Skin Cancer Treatment Is Better?

Mohs surgery is the best treatment option for most skin cancers. This tissue-sparing procedure offers high cure rates and excellent outcomes, especially if the lesion is removed early. However, patient factors and some tumor characteristics can limit its usefulness in certain situations. Wide local excision is an alternative if a patient cannot have a Mohs procedure.

Finally, if you have a skin problem that’s been bothering you for a while, it may be time to visit your dermatologist. Board-certified dermatologists are specifically trained to diagnose and treat common and rare skin lesions. The earlier you get rid of that blemish, the sooner you can recapture your radiant skin and peace of mind.

Author: Don Mehrabi

Don Mehrabi, MD, FAAD, is LA’s leading board-certified dermatologist who treats patients, builds the BHSkin clinics, and raises three kids. This blog builds on medical studies combined with Dr. Mehrabi's first-hand experiences from practicing in Encino-Tarzana, Glendale, and online