Advancing the Science

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May 12, 2020

Melanoma surgery: When more isn’t necessarily better

By Elizabeth Zimmermann
close in shot of medical supplies and a printout about skin cancer with 'melanoma' highlighted.

When you have a chance for an extra scoop of ice cream, that extra might be nice. If you are trying to fit into last summer's bathing suit, another inch off is probably welcome. However, if you're having surgery to remove melanoma, like Goldilocks choosing a bowl of porridge, you want a procedure that's 'just right.'

According to the American Cancer Society, skin cancers are the most common of all cancers. Melanoma only accounts for about 1% of these, but leads to the majority of skin cancer related deaths. Typically a melanoma tumor will be surgically removed —along with other treatment, depending on the stage of the cancer. What is not so typical is who does these surgeries, and where these surgeries are performed.

To reduce the resultant variability in care, the National Comprehensive Cancer Network issued guidelines for both patients and surgeons for the treatment of melanoma.

Maria Huayllani Peralta, M.D., a research fellow in Plastic Surgery on the Jacksonville, Fla., campus of Mayo Clinic, wanted to see if clinicians were following these guidelines. She and a multidisciplinary group of physicians and scientists from Mayo Clinic recently published the results of their investigation in Anticancer Research — International Journal of Cancer Research and Treatment.

"Melanoma surgery can be performed by surgeons of different specialties such as dermatologists, surgical oncologists, and reconstructive plastic surgeons," says Dr. Huayllani Peralta. "For that reason, guidelines to perform a safe excisional surgery to avoid recurrence were developed. However, we noticed that the specific guidelines for treating invasive melanomas were not always followed, so we decided to look exactly why this was happening."

Melanoma is a cancer that starts at skin level and spreads both in width and depth. Surgical removal can leave visible and often disfiguring scars or disabling gaps in flesh.

When removing a melanoma tumor, surgeons use what is called a 'wide excision' to remove the entire tumor, along with a small amount, or margin, of normal tissue around the tumor. The guidelines prescribe the appropriate margins for each tumor stage and size.

"Following established guidelines gives patients the safest surgical removal possible, taking the adequate amount of normal tissue while ensuring the tumor is completely removed," says Antonio J. Forte, M.D., Ph.D., a plastic surgeon at Mayo Clinic, and the senior author of the study.

However, he and Dr. Huayllani Peralta and the rest of their team found that in many cases, much bigger margins are being removed than is necessary.

The data and research findings

Besides plastic surgery, their research team included experts in several areas, including health care outcomes research, surgical oncology and biomedical statistics. Supported by the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, this project and others like it are part of Mayo's ongoing efforts to improve outcomes, experience, and indeed, the overall value of health care. 

As part of this partnership, Aaron Spaulding, Ph.D., a researcher in the Mayo Clinic Kern Center for the Science of Health Care Delivery, played a key role, says Dr. Forte.

Dr. Spaulding speaks to the evidence. "We would like to improve the health care of patients with invasive melanoma. By better understanding the current management of patients with invasive melanoma we can better identify successes and potential gaps in that care process," he says. "This can then provide the evidence needed to improve clinical training and recommendations to treat these patients."

"As an academic medical center, we able to foster the development of researchers and physician scientists through multiple research education programs," says Dr. Forte. "This also allows us to leverage experts from a variety of different fields to contribute to research and find solutions for our patients, and people everywhere."

The team used the National Cancer Database, which represents more than 70% of newly diagnosed cancer cases nationwide, to find patients diagnosed with invasive melanoma in the U.S., between 2004 and 2015.

Initially they found 525,271 adult patients. The investigators excluded patients with melanoma in situ, or stage 0, which can be treated without wide excision surgery. They also removed patients with incomplete information, misclassification, or who did not fit the study criteria of primary local invasive melanoma without metastasis.

According to National Comprehensive Cancer Network guidelines, the smallest tumors — less than or equal to 1 mm thick — should have a 1 cm margin.  Somewhat larger tumors should be  removed with a 1-2 cm margin, and tumors greater than 2 mm thick should have a 2 cm margin.

Due to database limitations, all tumors ≤ 1 mm thick that had been removed with the appropriate 1 cm margin were not considered for the study. In the confines of this study, the investigators also did not look at margins that were smaller than recommended.

They then reviewed the tumor thickness and surgical margins for the remaining 26,440 patients.

Among these patients, the researchers found that nearly half (48.7%) had received wider than recommended margins. Of these, a majority — 7,182 — were patients who had tumors no thicker than 1 mm, and of those 2,236 had excessively large margins (greater than 2 cm). These excessively large margins were seen with larger tumors too.

The findings, next steps

The investigators wanted to determine who was removing extra tissue, and why. They found a few factors that seemed to contribute:

  • Tumors located in the trunk — as opposed to head, neck or other more visible areas — were more likely to be removed with larger margins.
  • Tumors greater than 1 mm were more likely to have appropriately-sized margins when removed in an academic medical setting.

The research team did not find any difference in overall survival rates, suggesting that the excessive margins did not add to life expectancy.

"Knowing that removing more tissue than the guidelines recommend doesn't lead to better life expectancy, it is even more important to consider other patient outcomes," says Sanjay Bagaria, M.D., a surgical oncologist and study co-author. "For example, wider than recommended excisional margins may affect adjacent skin and would need further reconstruction techniques.

"At the same time, the application of these reconstruction techniques such as skin grafts and flaps will bring additional surgical risk and potential complications, such as infection, tissue necrosis, and deformity," continues Dr. Bagaria.

Guidelines help physicians to act based on the best evidence available, he says.

Dr. Huayllani Peralta says they published their findings and are sharing their research in other venues to encourage surgeons across specialties to follow guidelines. "We want to make a strong recommendation of adhering to the NCCN guidelines for patients with invasive melanoma," she says. "We believe this study strengthens current knowledge regarding the management of these cases."

Her thoughts are echoed by Dr. Forte. "Research and education are significant components in the Mayo Clinic three-shield philosophy," he says. "We not only want to provide the best possible care for our patients — based on the current established guidelines, but also to build the evidence base supporting care decision. And then pass our knowledge along through publication, training and other educational mechanisms."

Dr. Huayllani Peralta received her medical degree from Universidad Nacional Mayor de San Marcos in Peru, and is at Mayo Clinic to gain research experience in plastic surgery. "Research is needed to improve the health care and find the best management to restore defects or deformities that cause functional and structural impairment in patients," she says. Someday she hopes to be able to repair birth defects and perform other reconstructive surgeries to help people recover both physical structure and function.

As Dr. Huayllani Peralta's mentor, Dr. Forte says, "It’s part of my mission to leverage my experience as a surgeon-scientist and contribute to the growth of my mentees." Guiding her in this study was one such opportunity for Dr. Forte.

And for both of them and the rest of the research team, this study provided a chance to learn, and share what they learned.


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Tags: Aaron Spaulding, Antonio Forte, Center for the Science of Health Care Delivery, dermatology, Findings, Maria Huayllani Peralta, Mayo Clinic Cancer Center, melanoma, News, plastic surgery, Sanjay Bagaria, surgery, surgical outcomes

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