Mohs surgery remains go-to option when tissue preservation is a priority

National report - When tissue conservation is critical, Mohs surgery remains the standard of care in skin cancer removal, allowing clinicians greater margin control than some treatment alternatives.

Mohs surgery is an effective, efficient and safe technique for skin cancer removal, and could be considered as an ideal treatment approach in numerous scenarios in skin cancer surgery, according to David G. Brodland, M.D.

Several different techniques are used in the removal of cutaneous cancers, such as standard excision and Mohs surgery as well as numerous destructive modalities, including electrodesiccation and curettage (ED&C), CO₂ laser vaporization, cryosurgery, and curettage, says Dr. Brodland, dermatologist and Mohs surgeon, Shadyside Medical Center, Pittsburgh. Mohs surgery can be particularly useful, however, when tissue conservation and careful margin control is deemed critical.

“One of the primary indications for Mohs surgery is when tissue conservation is paramount. Tumors located around the eyelid, nose, lip, ear, finger and genitalia would be ideal indications for the technique, or any area where function or appearance could be compromised with excessive tissue loss,” says Brad Merritt, M.D., assistant professor, department of dermatology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, N.C.

Case selection

Conservation of tissue is clearly more of an issue in younger patients who typically do not have any redundant skin and in whom the general cosmesis of surgical outcome can be extremely important compared to patients of advanced age.

According to Dr. Brodland, other primary indications for Mohs surgery can include scenarios where biopsy reveals an aggressive histologic subtype of any cutaneous cancer, when tumor size is greater than 2 cm anywhere on the body, as well as in recurrent tumors or tumors that have been treated in the past with other techniques and have recurred despite concerted efforts to remove the lesion.

Drs. Brodland and Merritt recently spearheaded a four-week, 13-site, 13-Mohs surgeon, prospective cohort study evaluating the rate of complications and postoperative pain associated with the treatment of skin cancer using Mohs surgery with and without reconstruction in 1,550 patients with 1,792 tumors.

Study data

The specific treatment approaches varied among individual surgeons in the study including the use of intraincisional/peri-incisional antibiotics, preoperative antibiotics, postoperative antibiotics and postoperative analgesics.

Demographic information including medications and smoking status, tumor characteristics, number of stages, use of antibiotics, wound management, and use of postoperative analgesics were all recorded. Complications occurring during Mohs surgery and within two weeks of surgery, as well as peak postoperative pain levels were documented. Follow-up was obtained in 1,709 of 1,792 of cases (95.3 percent).

The study included a variety of neoplasms predominantly located on the head and neck, the majority of which were basal cell carcinoma (61 percent) and squamous cell carcinoma (31 percent). The mean preoperative size of lesions was 1.14 cm while the mean defect size was 1.89 cm. The number of stages performed ranged from 1 to 8, with a mean of 1.6. Of all cases, 82 percent of the defects were reconstructed and 18 percent were managed using second intention healing.

Data showed that no major complications occurred during Mohs surgery or reconstruction. Only 44 (2.6 percent) primary minor complications occurred in the 1,709 tumors with follow-up, the most common of which was active bleeding followed by infection, necrosis and hematoma.

“Our study showed that 97.4 percent of tumors were treated without complication, which speaks for the safety and efficacy of Mohs surgery. This study, the largest of its kind, reflects the success of Mohs surgery across the country in both academic institutions as well as in private practice,” Dr. Merritt says.

Surgical complications

Eight secondary minor complications occurred in the study, in which patients with one complication experienced another. While infection was considered the primary complication in patients who developed dehiscence or necrosis, active bleeding following surgery was considered the primary complication in patients who developed a second complication.

Active bleeding was found to be the most common complication, but out of the 21 patients who experienced this complication, 13 patients were taking anticoagulant medication. Three of the 21 patients also developed a minor secondary complication including a focal dehiscence, focal 10 percent necrosis, and hematoma.

According to Dr. Merritt, the minor complications that occurred were associated with older patients who had larger preoperative tumor and larger postoperative defect sizes. Also, patients who underwent a repair with a flap, graft or combination were more likely to experience a complication compared to those patients who underwent linear repair.

A total of sixteen patients in the study were treated for infection, of which four also developed wound dehiscence. Data showed that the incidence of infection was higher in those who healed by second intention or who underwent an interpolation flap. Moreover, the incidence of infections was lower in linear repairs compared to all other wound management approaches.

The intraincisional/peri-incisional and postoperative prophylactic antibiotic use varied by surgeon and repair type, and not surprisingly, none of the 126 patients given a postoperative prophylactic antibiotic developed an infection. The incidence of infection would likely be lower if everyone was treated with prophylactic antibiotics, Dr. Brodland says; however, there is a downside to this approach.

“Not quantified would be the number of people who develop adverse reactions to the antibiotic itself, such as rashes, nausea, vomiting and diarrhea. Moreover, there could be a selection of resistant bacteria and the last thing we need is another sub-type of MRSA (methicillin-resistant Staphylococcus aureus) to complicate the picture, which is the danger associated with the blanket use of antibiotics,” Dr. Brodland says.

Postsurgical assessment

A higher mean pain score was recorded in those patients who had a complication compared to those without and in these cases, the pain was mostly attributable to patients with postoperative infection. On a scale from 1 to 10, the average pain score of patients in the study was around 2, with 91 percent of patients reporting satisfaction with their postoperative pain control.

According to Dr. Brodland, the pain associated with Mohs surgery is remarkably low, which can be comforting for patients to know because many assume the procedure will be painful.

“I think one of the key points we learn from this study is that the pain is associated with complications, and the pain perceived by the patient should serve as a warning sign,” Dr. Brodland says. “Clinicians should be alerted to the patient who is complaining of pain more than what is expected, as this might indicate that there is a complication brewing.”

Mohs surgery is sometimes criticized for being expensive, Dr. Brodland says, and that it isn’t valuable or as valuable as proponents claim it to be. Though it is difficult to put a value on safety, he says that one could argue in favor of Mohs being value-added.

“I think that if one could put a value on safety, and we have proven that Mohs is a safe procedure, then if there is more cost associated with Mohs surgery, the reimbursement is worth the benefits one can reap from the procedure, particularly in the long-term,” Dr. Brodland says.

Mohs surgery is associated with a very low recurrence rate and therefore, there is a rare need for reoperation/re-excision of a recurring cancer. Although Mohs surgery is more expensive than destructive modalities such as laser or ED&C, Dr. Brodland says Mohs has the great benefit of intraoperative histology and the confirmation of definitive tumor clearance. The technique can also be very useful in the removal of melanoma in situ and superficial spreading melanoma (less than 1 mm thickness).

Particularly with the addition of the MART-1 immunostain, Dr. Merritt says that histology is now much easier to interpret in terms of whether there are atypical melanocytes or melanocytic proliferation.

“Some people have a sense that Mohs surgery is not well tolerated or is a highly invasive treatment, and while the process can be challenging, the majority of patients who undergo Mohs surgery do extremely well during and after the procedure. Mohs surgery has a very low complication rate, as well as the highest cure rate for the majority of skin cancers, making it a valuable tool in the management of patients with skin cancer,” Dr. Merritt says. DT

Drs. Brodland and Merritt report no relevant financial interests.