Operation Mohs , developed in 1938 by a general surgeon, Frederic E. Mohs, is a microscopically controlled surgery used to treat common types of skin cancer. During surgery, after each tissue lift and when the patient is waiting, the tissue is checked for cancer cells. The examination informed the decision to remove additional networks. Mohs surgery is one of many methods for obtaining complete marginal controls during removal of skin cancer (CCPDMAÃ, - circumference analysis and complete circumference edge rating) using frozen histology. CCPDMA or Mohs surgery makes it possible to remove skin cancer with very narrow operating limits and high healing rates.
The cure rates for the Mohs surgery cited by most studies are between 97% and 99.8% for primary basal cell carcinomas, the most common type of skin cancer. The Mohs procedure is also used for squamous cell carcinoma, but with a lower healing rate. Recurrent basal cell cancer has a lower cure rate with Mohs surgery, more in the 94% range. It has been used in the removal of melanoma-in-situ (cure rate of 77% to 98% depending on the surgeon), and certain types of melanoma (52% cure rate).
Other indications for Mohs surgery include protuberance dermatofibrosarcoma, keratoacanthoma, spindle cell tumor, sebaceous carcinoma, microcystic adnexal carcinoma, mercell carcinoma, Paget's disease of the breast, atypical fibroxanthesis, and leiomyosarcoma. Because the Mohs procedure is micrographically controlled, it provides the proper removal of cancer tissue, while healthy tissue is not necessary. Mohs surgery can also be more cost-effective than other surgical methods, when considering the cost of surgical removal and a separate histopathological analysis. However, Mohs surgery should be provided for the treatment of skin cancer in anatomic areas where tissue preservation is of the utmost importance (face, hands, feet, genitals).
Video Mohs surgery
Usage
Mohs surgery should not be used on the trunk or extremities for uncomplicated non-melanoma skin cancer less than one centimeter in size. In this part of the body, the risks outweigh the benefits of the procedure. Because of the high risk of recurrence among other reasons, Mohs surgery may be considered for skin cancer in the hands, feet, ankles, shins, nipples, or genitals.
Maps Mohs surgery
Technique
In 2012, the American Academy of Dermatology publishes appropriate use criteria (AUC) on Mohs micrograph surgery in collaboration with the following organizations: American College of Mohs Surgery; American Society for Mohs Surgery; and the American Society for Dermatologic Surgery Association. More than 75 doctors contributed to the development of the Mohs AUC surgery, published in the Journal of the American Academy of Dermatology and Dermatologic Surgery.
The Mohs procedure is a pathology division method that allows for a complete examination of surgical margins. This is different from the standard bread-division technique, in which a random sample of surgical margins is examined.
The Mohs operation is done in four steps:
- Surgical removal surgery (Oncology of Surgery)
- Mapping pieces of tissue, freezing and cutting tissue between 5 and 10 micrometers using cryostat, and staining with hematoxylin and eosin (H & amp; E) or other stains (Including Toluidine Blue)
- Microscope slide interpretation (Pathology)
- Possible reconstruction of surgical defect (Surgical Reconstruction)
This procedure is usually performed at a doctor's office under local anesthesia. Small scalps are used to cut out visible tumors. Very small surgical margins are used, usually with 1 to 1.5 mm "free margin" or uninvolved skin. The amount of free margin removed is much less than the usual 4 to 6 mm required for standard excision of skin cancer. After each surgical removal of the tissue, the specimen is processed, cut into the cryostat and placed on the slide, stained with H & amp; E and then read by a surgeon/pathologist Mohs who examined parts for cancer cells. If the cancer is found, its location is marked on the map (tissue withdrawal) and the surgeon removes the cancer tissue indicated from the patient. This procedure is repeated until no further cancer is found. Most cases were later reconstructed by surgeon Mohs.
This method is well explained in the current reference. Maloney, Mary E. (1999). Dermatopathology Surgery . Malden, Mass: Blackwell Science. ISBN: 978-0-86542-299-5. Ã, & lt;/ref & gt; Mapping combined with the "smashing the pie pan" method is the core of CCPDMA operations. If one imagines a pot of aluminum pie as the surgical edge covered in blood, and the top of the pie is a crust-covered skin surface - the goal is to flatten the aluminum pie pan into a flat sheet, mark it, dye it, and examine it under a microscope. Other authors use examples of peeling skin from oranges. Imagine an orange cut in half as a CCPDMA layer. The skin is the limit of surgery. One can remove this skin and flatten it on a glass slide to check for invasive cancer roots. The mapping is how people color and mark sections for microscopic examination. The parts can be processed in one piece (using casual incisions at some point, or hemisection like the figure of "Pac-Man"), cut in parts, cut in quarters, or cut some parts. Single piece processing is acceptable for small cancers, and some piece pieces facilitate processing and prevent artifacts. Single piece pieces prevent errors introduced by soft and hard-to-handle networks; or from accidental dropping or mislabeling of specimens. Dual divisions prevent compression artifacts, tissue separation, and other logistical problems by handling large thin sheets of frozen skin.
Some doctors believe that the histology of the frost is similar to that of Mohs's micrographic surgery, but not always. Mohs surgery is performed using fresh tissue while the histology of the frost section may or may not be CCPDMA. Non-CCPDMA histology typically uses a random network sampling technique called "bread loafing". Bread loafing is a statistical sampling method that examines less than 5% of the total surgical margin (imagine pulling 5 slices of bread out of whole bread slices and checking just 5 slices to visualize the whole bread). In CCPDMA processing, all surgical margins are examined (imagine the person checking the entire outer skin of the same bread). Statistically, the more bread is checked, the lower the "false negative" level will become. False negatives occur when a pathologist reads cancer excision as "residual carcinoma free", although cancer may be present in the wound and undetectable due to random sampling. The alternative to Mohs surgery is surgical excision of CCPDMA surgery and non-CCPDMA surgical excision. The pathologist Mohs and CCPDMA have perfected a method of examining all surgical margins, including new processing devices that decrease false-negative numbers.
Operation Mohs often leave open sores, most often reconstructed (closed) by surgeon Mohs.
Mohs surgical team
The team consists of Mohs surgeon, histopathologist, and nurse aide. Mohs surgeon identified the cancer and its margins, often with the help of dermatoscopy. It elevates the cancer under local anesthesia and prepares it for histological processing. This is done by cutting the specimen (if required), coloring the specimen for orientation, and sending it to the lab.
The histotechnician prepares the tissue to process Mohs by leveling the surgical margins on the first flat surface. Then a flat surgical surface is mounted on the cryostat to be cut and prepared for slide glass to be read by a pathologist.
In Mohs surgery, the surgeon acts as a pathologist. He examined the slides for the remaining tumors, and marked the location of the tumor on the pathology report.
Mohs surgeon most often functions as a reconstructive surgeon.
The coloring convention
Each surgeon has his own convention. The general conventions are as follows
Epidermis l l l l l BLUE - - - - - - - - - Â RED --------------------------------- YELLOW O O O O O O GREEN X X X X X X X Missing Epidermis V V V V V V V V V
Difference between histology of cross section and vertical section
Sometimes, for the purpose of confirmation, a second opinion will be required from a pathologist to review the pathology slide of the Mohs case. Traditional histology of skin tissue using vertical cleavage - with subcutaneous tissue at the bottom and epidermis at the top. The Mohs operation uses tangential or horizontal divisions, which can confuse pathologists trained in traditional methods.
First, we must specify the method of encoding or color coding. Mohs map orientation should be able to distinguish between medial, lateral, superior, and inferior.
Next, one must determine whether the surgeon follows the convention of installing only 2 parts per case; as some authors like; or whether he is doing serial division via block as preferred by other authors. If serial division is performed, the spacing between sections must be confirmed. Some surgeons use 100 micrometers between each part, and some use 200 micrometers between the first two parts, and 100 micrometers between the next parts (10 crank tissue set at 6 to 10 micrometers approximately equal to 100 micrometers if possible for physical compression due to the blades).
Next, one determines whether the entire epidermal boundary is present. Ideally 100% of epithelial boundaries must exist. The Convention requires at least 95% of the epidermis to be present. However, some surgeons will make exceptions for some missing epithelials in the apex of elliptical excision around the specimen. Ideally, the oval should be done. However, for the practical purpose of some lesions, a surgeon may bypass the Mohs part to estimate the final closure flaw. The peak is often 1 cm or more of the tumor, so a clear margin on the apex can be ignored. This is not an ideal by convention, but is on a case-by-case basis.
Next, one determines whether the surgical margin is clear. With serial sectioning, we must recreate the surgical specimen in a 3-dimensional way. The first part that touches the blade starts a 3-D reconstruction. Using a 3-D specimen reconstruction, one can say that all epithelial margins are present when one develops from within to the surface. If only 2 parts exist, ideally, the two parts should be clear. If the deeper part is positive, we must ensure the distance between the parts. Conventions often require a clear margin of at least 200 micrometers. For ambiguous structures that resemble adnexal and carcinoma structures, following the serial part will allow one to identify the structure as benign or malignant. With the 2 slide method, this may be impossible, because 3-D reconstruction is not possible with only 2 parts.
The appearance of carcinoma under the division of Mohs micrography can be difficult. Squamous cell tangential pieces may resemble squamous cell carcinoma (but without atypia). The passage through the hair follicle buds may resemble those islands that are isolated from basal cell cancers, often even with retracting artifacts. Serial section analysis is best for Mohs operations.
Mohs operation and blood thinner
The tendency in skin surgery over the past 10 years has continued anticoagulants while performing skin surgery. Most skin bleeding can be controlled by electrocautery, especially bipolar pliers. The benefits gained by ease of hemostasis are weighed against the risk of stopping anticoagulants; and it is generally preferred to continue the anticoagulant.
Risks and complications
Rate cure
Some specialists disputed the cure rates for Mohs, especially pathologists who are familiar with this procedure. Extensive research conducted by Mohs involves thousands of patients with fixed tissue and fresh tissue cases have been reported in the literature. Other surgeons repeated the study with thousands of cases, with almost the same result.
5 years clinical healing rate with Mohs surgery:
- 4085 cases of primary and recurrent cancers of the face, scalp, and neck. 96.6% healing rate.
- 1065 cases of squamous cell carcinoma of the face, scalp, and neck - healing rate of 94.8%
- 2075 cases of basal and recurrent basal cell cancer, 99.1% cure rate.
- Healing rates for basal cell cancers of the ear, less than 1 cm, 124 cases, 100% cure rate.
- Healing rates of basal cell cancers of the ear, 1 to 2 cm, 170 cases, 100%. We need to remember that the cases done by Mohs were for large and extensive tumors, often treated many times before by other surgeons. Regardless, the recovery rate for small primary tumors is 100% or close to 100% when separated from larger or recurrent tumors.
This is only a small number of cases reported by Mohs, and many other articles by other authors have shown remarkable rates of healing for primary basal cell carcinomas. Study by Smeet, et al. showed Mohs healing rate of about 95%, and other studies in Sweden showed Mohs cure rates of about 94%.
Variations of healer speed
Mohs surgery is not the answer to all skin cancers.
In fact, Mohs micrograph surgery is nothing more than a frozen histology using unique peripheral peripheral tissue processing techniques. There is nothing magical about his recovery rate or why years of training are required. When compared to many peripheral marginal network processing techniques described - the end result is the same - allowing for a complete 100% examination of the surgical limit. This method is unique only because it is a simple way to handle soft tissues that are hard to cut. Once studied, the pathologist who is currently performing the frozen histology will realize how simple this technique is. This is better than doing bread bread rolls at 0.1 mm intervals to increase the false negative error rate takes less time, fewer network handling, and fewer glass slides are installed. Once installed as a tangential or horizontal part, the pathologist should only re-examine how to visualize the skin structure at a tangential to horizontal view. In the absence of a trained Mohs pathologist, the peripheral part followed by the horizontal division of the remaining center is similar, but not exactly the same as the Mohs method.
Clinical excerpts for Mohs surgical recovery rates were from 97% to 99.8% after 5 years for newly diagnosed basal cell cancer (BCC), decreased to 94% or less for recurrent basal cell cancer. Radiation oncologists cite cure rates of 90 to 95% for BCC less than 1 or 2 cm, and 85 to 90% for BCCs greater than 1 or 2 cm. Surgical excision healing rates vary from 99% for the width of the margins (4 to 6 mm) and small tumors, to as low as 70% for the narrow margins applied to large tumors. Here the weakness of the procedure is the histopathological process, and not the surgeon himself. The surgeon's error is a lack of understanding of pathology laboratory methods, and fails to follow the standard of care for adequate surgical margins. Typically, the healing rate using standard bread is very low for narrow surgical margins and large tumors, and very high for large margins in small tumors.
Society and culture
Overload and cost
Some dermatologists, oncologists, and health economists say that Mohs operations are excessive, because they are very profitable. The dermatologist may perform surgery on areas of the skin where unnecessary, or perform unwanted cosmetic surgery. Incident surgery Mohs increased by more than 400% in 10 years. In a sample of 100 Mohs operations, the cost ranged from $ 474 to $ 7,594, at a higher cost to hospital-based physicians. In 2010, hospital-based dermatologists who performed the Mohs surgery were paid $ 586,083, according to the Becker Hospital Review. When the operation is performed in different steps by different specialists, each specialist may bill his or her own procedures, such as the surgery itself, covering the wound, anesthesiology, and facility costs. This can amount to more than $ 25,000 for a single procedure.
History
Initially, Mohs used a chemical paste (escharotic agent) to burn and kill tissue. It is made of zinc chloride and blood roots (plant roots Sanguinaria canadensis , containing sanguinarine alkaloids). The original material was 40.0 grams Stibnite, 10.0 gm Sanguinaria canadensis, and 34.5 ml saturated zinc chloride solution.
This paste is similar to black ointment or "Hoxsey paste" (see Hoxsey Therapy), fake patent medication, but its use is different. Hoxsey used pasta for a long time, a dangerous practice that was quickly discredited. Mohs left the pasta on the wound overnight, and the next day, the cancer and surrounding skin will be anesthetized and the cancer removed. The specimen is then cut, and the tissue is examined under a microscope. If the cancer persists, more paste is applied, and the patient returns the next day. Later, local anesthesia and frozen histopathology applied to fresh tissue allowed the procedure to be performed on the same day, with fewer tissue damage, and the same cure rate.
References
External links
- The American Cancer Society's statement on the treatment of basal cell carcinoma, including through Mohs surgery
Source of the article : Wikipedia
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