JAMA Study Highlights Precision As The Key To Success in Mohs Surgery

HumAdminDermatology & Skin Cancer Center, Mohs Surgery, Southern Dermatology News & Articles, The Triangle Physician, Uncategorized

Mohs surgery

Skin cancer affects people of all ages, sizes and skin types. It is the most common form of cancer in the U.S., with more than one million skin cancers diagnosed annually. In fact, one in five Americans will develop skin cancer in the course of a lifetime, and more than 20 Americans die each day from skin cancer—primarily melanoma. The survival rate for patients whose melanoma is detected early, before the tumor has penetrated the epidermis (outermost layer of the skin), is about 99 percent. Therefore, early detection and treatment are the key to success in treating most skin cancers.

Several techniques are available to physicians in their effort to combat the long term effects and mortality rates of skin cancer. Those include, but are not limited to:

  • simple excision
  • Mohs micrographic surgery
  • cryosurgery
  • topical chemotherapy
  • radiation
  • photodynamic therapy

Each of these has unique benefits and may be used in various circumstances. However, during the past 80 years, Mohs surgery has probably gained the most traction and acceptance in the medical field.

Mohs micrographic surgery is the gold standard of treatment for skin cancer in the U.S. and is a widely accepted surgical procedure around the world. Simply stated, Mohs micrographic surgery requires applying a local anesthetic to the cancerous site on a person’s skin, and then removing thin layers of the epidermis—one layer at a time—until the cancer cells are no longer present. Standard practice requires that each layer of skin is first analyzed and mapped under a microscope before additional layers are removed. Mohs micrographic surgery usually does not require overnight hospitalization, and it is typically completed within a few hours at both group and solo practitioners’ offices.

Dr. Frederick Mohs, the inventor and father of Mohs surgery, experimented on his first human patient on June 23, 1936. This, of course, was not perfected without some trial and error. But since then, Mohs surgery has proven to be almost 99% effective at removing skin cancer. (It is not used for internal or organ cancers within the body.) In fact, in 1985 President Reagan had Mohs surgery to remove a cancerous site on his nose.

Prior to Mohs, physicians were limited in the way they treated skin cancers. Usually, surgical removal of the tumor, curettage and electrodesiccation and radiation were the options and methods used to treat various skin cancers. Dr. Mohs and his work laid the foundation for skin cancer treatment, but improving and building on past techniques is an ongoing continuing education for all who practice medicine.

[See the diagrams outlining the procedure.]

Stage 1: We clean, mark and inject the area to be treated with a local anesthetic. In just a few minutes, we remove the visible cancer along with a thin layer of additional tissue.

Stage 2: We cut the removed tissue into four sections, stain and mark it on a Mohs map diagram.

We freeze the tissue on a cryostat and remove very thin slices from the edges and undersurface. We then place the slices on slides, stain them and examine them under the microscope. This can take more than an hour.

We carefully examine the specimen and pinpoint all microscopic “roots” on the Mohs map diagram. If we find residual cancer on the specimen, we utilize the Mohs map to identify where to remove additional tissue. Additional tissue will only be removed when cancer is present.

Stage 3: We repeat the process outlined above until no remaining cancerous areas are found within a tissue specimen.

Stage 4: When there is no remaining cancer tumor under microscopic examination, we repair the surgical incision site.

In performing Mohs micrographic surgery, the ideal is to completely remove the cancer while leaving the normal tissue as untouched as possible. In Mohs surgery cases, the number of stages (or cuts) can vary greatly from physician to physician—with excessive cuts resulting in unnecessary surgery and financial burden for patients. This also negatively affects the healthcare system.

A report published in The Journal of the American Medical Association last June researched and examined the practices of Mohs surgery among a group of physicians over three years. Some 2,305 physicians were included in the study and were categorized according to sex, experience (years in practice), whether they were a member of ACMS or practiced at an Accreditation Council for Graduate Medical Education site, group practice or solo practice, the number of procedures, and rural vs urban locations. Also, physicians had to have performed at least 10 Mohs surgeries each year to be included in the study. The study’s conclusions were as follows:

There was marked variation in the mean stages per case per physician for MMS. The mean for all physicians practicing from January 2012 to December 2014 was 1.74 stages per case, the median was 1.69 stages per case, and the range was 1.09 to 4.11 average stages per case with interquartile range 1.51 to 1.89 stages per case and remained consistent in all 3 years investigated. The high outlier status cutoff point was 2.41 stages per case based on the aggregate of data from all 3 years. […]

Practicing MMS in a solo practice was associated with a 2.35-times likelihood of being a persistent high outlier (95% CI, 1.25-4.35). Overall, 4.5% of solo practitioners (17 of 359) were persistent high outliers compared with 2.1% of physicians who perform Mohs surgery in a group practice (28 of 1337). Persistent high outlier status was not associated with sex, practice experience, case volumes, ACMS membership, practicing in an ACGME training site, or geographic location.

The study suggests that informing physicians of the prevalence of unnecessary practice methods (i.e., the negative impact of making more cuts) may help ensure that their patients receive adequate medical treatment. The journal also concludes that physicians, with proper training and oversight, will be (and should be) making fewer cuts when using the Mohs method in the future.

Mohs surgery is an exacting procedure, and studies like this one will help assist all physicians in understanding proper techniques and practices to remove only diseased tissue, preserve healthy tissue and minimize the cosmetic impact of the surgery. This will, in turn, save time and result in better outcomes for patients with lower medical costs.