Overview of Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
Mohs micrographic surgery, or MMS, is a very careful surgical procedure that is used to remove certain types of skin cancers such as basal cell carcinoma and squamous cell carcinoma. Even though it is mostly used for these skin cancers, it has proven to be effective in treating melanoma in situ (a type of skin cancer that is only in the outermost layer of skin) and invasive melanoma (a type of skin cancer that has spread deeper into the skin), providing particularly good results in managing the disease and preserving the appearance of the skin.
This surgery was developed by and is named after Dr Frederic Mohs. His method allows doctors to control and see the exact border of the tumor while preserving as much healthy skin as possible. This is especially crucial for skin cancers that are difficult to remove completely, likely to come back, or could result in a significant loss of skin. Initially, this treatment was called “chemosurgery”, where they would apply a chemical fixative (such as zinc chloride) to the cancer, which they would then remove and examine under a microscope. Over time, this technique has evolved to involve processing fresh tissue rather than applying a fixative, then freezing, and cutting it in a device called a cryostat microtome. This allows for faster processing, decreases discomfort for the patient and also helps to preserve more of the tissue.
MMS is particularly useful in managing skin cancers because it allows doctors to completely control and see the cancer’s margins (edges), all while preserving the surrounding healthy skin. This is important for skin cancers that are hard to completely remove or are likely to come back, and in situations where preserving the tissue is crucial. There have been numerous studies that show MMS to be promising in the treatment of melanoma. Given their tendency to spread beyond what can be seen with the naked eye, MMS is an appropriate option for managing melanoma in situ and invasive melanoma. It is also associated with better results in tumor removal and in preserving the appearance of the patient’s skin.
Anatomy and Physiology of Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
Mohs Micrographic Surgery (MMS), a skin cancer removal technique, is particularly useful for sensitive and visible areas of the body such as the face, neck, hands, feet, and genitals. These areas are also susceptible to hidden extensions of skin cancer, which can be detected using MMS. Features like the lips and eyelids are not only visually important but also vital to normal functionality. If altered, they can result in significant changes to a person’s appearance.
However, if there isn’t much extra skin in the area operated on (known as tissue redundancy), repairing the area after performing MMS can be difficult. This is because removing a large area of tissue can lead to distortion of the adjacent body structures. In simple terms, it’s similar to removing a large piece of fabric from a tightly sewn patchwork quilt – the surrounding pieces can get distorted.
Why do People Need Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
Mohs micrographic surgery (MMS), a form of surgery for skin cancer, is usually needed for skin cancers that are likely to come back, haven’t been fully removed before, or when it’s important to save as much tissue as possible. There are certain guidelines doctors use to determine when this type of surgery is most suitable depending on individual patient details, where the tumor is located, and the characteristics of the tumor.
MMS has proven to be effective for the treatment of melanoma in situ (MIS) or invasive melanoma, particularly when it uses immune-based stains like melanoma antigen recognized by T cells 1 (MART-1). MMS allows for a detailed examination of the edges of the tumor before reconstructive surgery, which decreases the chances of the tumor returning. MMS is especially effective for treating melanomas in special areas of the body, like the head, neck, hands, feet, genitals, and the front of the leg, due to its detailed margin assessment, tissue conservation, and low recurrence rates.
Despite the success of MMS, there’s still debate around its use. According to the National Comprehensive Cancer Network (NCCN) guidelines, MMS isn’t recommended for invasive skin melanoma when standard clinical margins can be obtained. However, it should be considered for minimally invasive melanomas in anatomically complex areas like the ears and hands. When performing MMS for melanoma, larger surgical margins might be needed, particularly for large or poorly defined melanomas. The use of frozen immunohistochemical stains may help prevent the cancer from getting worse or returning, by providing a clearer view of the tumor margins.
This type of surgery fills in the gaps of the NCCN guidelines for melanoma removal. For example, wide local excision (WLE) effectively treats melanomas on the trunk and the area of the body closest to the center, but has less data supporting its use on special sites. The recurrence rates after WLE are only around 2% for melanomas on the trunk and close to the center of the body, but about 10% for melanomas in special sites. This makes it harder to decide the appropriate reconstruction time because it’s crucial to ensure the tumor removal before performing complex reconstruction.
In terms of MMS procedures, margins recommended by NCCN can be used, such as a 0.5 mm margin for MIS, and a 1.0 mm margin for T1a/b melanomas. Smaller initial margins might be used if the melanoma is in a crucial location or near a free margin. For example, 9 mm margins were found to remove 99% of melanomas compared to 86% with 6 mm margins. MMS can also be done on invasive melanoma with more than 0.8 mm depth, but in such cases, a biopsy of sentinel lymph nodes may be required before MMS, leading to two separate surgeries. Based on the depth of the MMS removal, it should at least reach the superficial fascia, which is a layer of connective tissue, as recommended for WLE by NCCN.
Various types of stains like MART-1, SRY-box 10 (SOX-10), and microphthalmia-associated transcription factor (MITF), are commonly used in MMS for melanoma. These stains are effective for various types of melanoma. They offer a clear outline of the cell nuclei of melanocytes — the cells that produce melanin, the pigment that gives skin, hair, and eyes their color.
While performing MMS for melanoma, the removed tumor may be prepared in a way that can be quickly frozen and examined, but this should also be sent for full pathology examination. The gold standard is permanent sections for removed melanoma because they provide a better assessment of the tumor than a quick frozen slice. For example, frozen sections may be less accurate in measuring the depth of an invasive tumor, spotting lymphovascular invasion, or diagnosing rare but aggressive melanomas like desmoplastic melanoma. Preparing removed material for full permanent pathology examination is an important step to determine the staging of the tumor, which helps to decide whether further treatment is required.
When a Person Should Avoid Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
For those who are healthy enough for surgery, there are no total reasons why Mohs Micrographic Surgery (MMS), a special type of skin cancer surgery, can’t be done to treat melanoma, a serious type of skin cancer.[1]
Patients who take blood thinning medications for a long time can usually keep taking their medication around the time of the surgery.[24]
Equipment used for Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
Mohs Micrographic Surgery (MMS), a type of skin cancer treatment, involves removing the cancerous tissue and examining it under a microscope. This process requires specific types of equipment in both the surgical and laboratory settings.
In the treatment room, good lighting and adjustable seating help the doctor to clearly see and get to the tumor. Before surgery, a kind of local anesthesia is commonly applied. This helps numb the area where the surgery is performed. The actual surgery usually involves the use of a scalpel (a small surgical knife), gauze to mop up any blood or other fluids, and an electric device that helps to stop bleeding.
In the laboratory, the removed tissue is examined under a microscope. To do this, the tissue is frozen and thinly sliced using a device known as a cryotome or cryostat. These slices are then placed on glass slides. The tissue on the slides is colored (or stained) with a compound called hematoxylin and eosin (H&E) and, if necessary, other special stains (immunostains). These stains highlight different parts of the tissue under the microscope and help the doctor to identify if any cancer cells are still present. Some labs may use a hood to prevent the people working in the lab from being exposed to the chemicals used in the staining process. In some cases, a machine known as an automatic stainer is used to color the slides. Once the slides are ready, they’re checked under a microscope by the surgeon to see if any cancerous cells remain.
After the tissue is removed and if any cancer cells still remain, the wound is sewn up (or sutured) using special threads of different sizes. A surgical repair tray, which contains tools like a needle driver for suturing, scissors for cutting threads, delicate forceps for grappling with delicate tissues, skin hooks for pulling skin back, and a scalpel for cutting, is used for this process.
Who is needed to perform Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ?
The Mohs surgeon is a specialized doctor who removes the tumor and then also examines the tissue around it to make sure all the cancer has been removed. They also handle the reconstruction process, which is the repair of the area where the tumor was located. They would need support from a surgical assistant during the surgery and a histotechnician, who helps analyze the tissue that’s been removed, in the lab. Sometimes another doctor, called a pathologist, might also check the removed tissue in a detailed and permanent way.
Preparing for Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
Before starting a Mohs micrographic surgery (also known as MMS, a certain type of skin cancer treatment) for melanoma (a serious form of skin cancer), doctors will give the patient local anesthesia. This numbing medicine is intended to make sure the patient is comfortable and doesn’t feel any pain during the procedure. A common anesthetic used is a mixture of lidocaine and epinephrine, which is scientifically known as “buffered 1% lidocaine with 1:100,000 epinephrine”. Relaxation and comfort are prioritized to make the treatment as bearable as possible for the patient.
How is Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ performed
Melanoma treatment using the Mohs Micrographic Surgery (MMS) involves many health professionals working as a team to ensure the best possible result. Before the surgery, the main surgeon may speak with specialists in departments such as Ear, Nose and Throat (otolaryngology) or cancer surgery (surgical oncology). This is to plan for a procedure called SLNB, which checks if the cancer has spread, in patients with an advanced form of melanoma. Conversations with pathology experts are key as they offer crucial information about what the cancer looked like during the initial biopsy and during the surgery. In more complex cases, such as melanoma affecting the nail or foot, a plastic surgeon may also be consulted, particularly when the procedure might involve a significant amount of tissue removal, amputation, or reconstructive surgery.
The MMS procedure for melanoma typically includes the following steps:
- The surgeon first draws the outline of the tumor and the intended margin – the area of healthy tissue surrounding the tumor that will also be removed – on the patient’s skin. This is all done before any local anesthetic is given to numb the area. The surgeon will also draw a map on paper, showing exactly where on the body the tumor is located.
- Then, the surgeon removes as much of the visible tumor as possible, a process known as “debulking”. This helps the surgeon prepare the tissue for processing and examination.
- The surgeon then removes a thin layer of tissue around and beneath the visible tumor. This could be done at a slight angle to help with the later examination of the tissue, but isn’t strictly necessary.
- The removed tissue is then marked with colored dyes for easier examination and identification, flattened, and processed to be examined in a lab.
- With the help of a microscope and special stains that highlight cancer cells, the surgeon and pathology team will check the removed tissue to see if any traces of melanoma are present.
- The process of removing and examining tissue layers is repeated until it is confirmed that all of the cancer has been removed.
- After the cancer is completely removed, the surgeon will close up the wound with stitches, skin grafts, or allow it to heal naturally. This process could be done either by the main surgeon or another surgical specialist such as a plastic surgeon or otolaryngologist.
- Finally, the patient will be monitored after the surgery for any complications such as bleeding, infection, or wound opening.
For some patients, a variant of this procedure called “slow MMS” may be used where the removed tissue is preserved in a chemical solution called formalin and examined over several days. This is often used when the quality of the frozen tissue sections is poor or when the fast process of frozen section analysis is not available.
Before undergoing MMS for melanoma, the surgeons recommend not to use a tool called a Wood lamp, which uses ultraviolet light to examine the skin, to identify surgical margins. However, dermatoscopes, which have a light source and magnifying lens, can be beneficial and are recommended.
Possible Complications of Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ
During the MMS surgical procedure, there can be a few complications. These include difficulties with the quality of the frozen samples used for testing, interpretation of these samples, handling of tissue samples, or issues with the direction of tissue. It can also be a tough task to differentiate between the increase in melanocytes, the cells responsible for skin color, in skin damaged by sun, as compared to melanoma, particularly with a type of melanoma known as acral lentiginous melanoma.
Certain complications might happen after the surgery, including wound death (1.9% of cases) and wound reopening (1% of cases). These complications are linked to larger defects and more complex repairs. Infections, delayed healing of wounds, and bleeding are other common problems. During MMS, sensory nerves, those that send messages from your senses to your brain, can often be disrupted, potentially leading to temporary or even permanent loss of feeling at the operation site. Motor nerves, which control movements, can also be disrupted when removing highly invasive tumors, possibly leading to temporary or permanent muscle weakness.
However, MMS is considered a pretty safe procedure. The chance of having a complication and the severity of those complications is low. A study looking into 20,821 cases in 23 locations showed that MMS was linked with a complication rate of 0.72% and a death rate which is virtually unnoticeable. Most complications can be managed in the clinic where the Mohs surgery took place.
A rare but possible complication of MMS for treating melanoma is that the tumor might come back or wasn’t completely removed. In these cases, further surgery should be considered. For patients who cannot go for further surgery, a topical cream called imiquimod or radiation therapy can be considered.
What Else Should I Know About Mohs Micrographic Surgery Management of Melanoma and Melanoma In Situ?
Mohs Micrographic Surgery (MMS), a type of skin cancer surgery that removes cancer layer by layer, has proven to be an effective treatment for melanoma, a type of skin cancer. The usage of specific dyes during this procedure, such as MART-1, help surgeons to see the edges of the cancerous area, making it easier to remove all the cancer cells.
The benefits of MMS go beyond its ability to remove cancer while leaving as much healthy tissue as possible, especially in areas where cosmetic results are important. The surgery is excellent at ensuring all cancer cells have been removed, which contributes to a low rate of the cancer returning. To put this into perspective, a study observed that after 123 melanomas were removed with MMS, only around 1.63% of the cases saw a return of the cancer.
Compared to other expected standard procedures like Wide Local Excision (WLE), a surgery that removes not only the cancer but also some of the healthy tissue around it, and staged excision, a method where the tumor is removed in stages, MMS is also noted to have a lower potential risk for the return of the cancer.
However, despite its benefits, MMS for melanoma comes with challenges. For example, more research is needed to be done to prove if MMS can improve survival rates compared to other methods like WLE or staged excision. In addition, because this is a relatively new method, not all surgeons who specialize in Mohs surgery have received formal training in using MMS for melanoma. Also, this surgery requires a well-equipped laboratory and staff that can handle the special dyes used in this surgery. Even then, due to the detailed nature of the procedure, the surgery could last for several hours. Despite these challenges, MMS offers benefits like reconstruction on the same day and the ability to minimize the chances of not removing all cancer cells and the cancer returning, which could lead to improved patient outcomes.
