High-Stage cSCC: Outcomes Superior With Mohs vs WLE

PHOENIX — Mohs surgery appears to be superior to wide local excision (WLE) in patients with high-stage cutaneous squamous cell carcinoma (cSCC), according to findings from a retrospective study. The benefit was seen across all outcome measures, including rates of recurrence, metastasis, and mortality.

These data support Mohs surgery as being the preferred surgical treatment option for high-stage cSCC, commented lead author David M. Wang, MD, Mohs Micrographic Surgery and Dermatologic Oncology Fellow, at Harvard-Brigham and Women's Hospital (BWH)/Dana-Farber Cancer Institute, Boston. "We found that across all outcomes, high-stage cSCC treated with WLE had a roughly twofold greater risk for recurrence, metastasis, or disease-specific death compared to Mohs," he said at the American College of Mohs Surgery (ACMS) 2024 Annual Meeting, where he presented the results.

External validation using data from a multicenter cSCC research collaboration from 12 contributing sites from across the United States, as well as international sites, was also conducted. "We performed the external validation by comparing results of the BWH only cohort, which was the primary study, with the full multicenter data and with the full multicenter data minus the BWH cohort, and the findings were nearly identical in all three analyses," Wang said.

Although patients diagnosed with cSCC usually have good outcomes, high-stage disease is associated with a higher risk for recurrence, metastasis, and death. Both Mohs surgery and WLE are used to treat cSCC, but a comparison of outcomes has not been well established in the setting of high-stage cSCC. Comparing the two surgical strategies can be problematic, as both patient and/or tumor characteristics can make it difficult to determine which outcomes can be attributed solely to the treatment type.

Mohs Superior Across the Board

In the retrospective cohort study, Wang and colleagues aimed to compare the results of Mohs surgery and WLE in patients with high-stage cSCC (BWH Staging System T2b or T3) and used statistical methods to balance baseline patient and tumor characteristics.

"To control for confounding by indication — differences in baseline patient or tumor characteristics — that are associated with both the treatment received and outcomes, we used propensity score weighting so that the baseline characteristics were balanced in the two treatment groups," Wang told Medscape Medical News. "This statistical method aims to simulate randomization in a randomized controlled trial such that any differences in outcomes after propensity score weighting is attributed solely to the treatment received."

The study used electronic medical records from a single tertiary care academic institution, and 216 patients with high-stage cSCC who had undergone surgery from January 2000 to December 2019 were included in the analysis. The median follow-up time was 33.1 months.

They found that overall, the risk for all adverse outcomes was lower among patients who had undergone Mohs surgery than among those treated with WLE, with the following results: Rates of local recurrence (5-year CI, 10.8% vs 22.1%, respectively; P = .003), nodal metastasis (11.9% vs 19.3%; P = .04), distant metastasis (4.7% vs 9.0%; P = .09), any recurrence (17.0% vs 34.2%; P < .001), and disease-specific death (8.5% vs 20.3%; P = .001).

"The data supports Mohs surgery as the preferred surgical treatment option for high-stage cSCC in accordance with NCCN [National Comprehensive Cancer Network] guidelines for very high-risk cSCC," Wang said. He pointed out that the terminology "very high risk" in NCCN equates to "high stage" in other staging systems (BWH T2b or higher, AJCC T3 or higher).

There is still "a substantial proportion" of patients with high-stage cSCC who are eligible for Mohs but are treated with WLE, he added. "Our hope is that these findings provide additional data to support Mohs as the standard of care for primary surgical treatment of high-stage cSCC."

Supports Benefits of Mohs

Weighing in on the research, Thomas E. Rohrer, MD, a dermatologic surgeon in Chestnut Hill, Massachusetts, noted that this was an excellent study that demonstrates benefits of Mohs surgery over straight excision on essentially all outcomes investigated and measured.

"The data clearly shows that Mohs should be used whenever possible," he said. "There are some patients and facilities that do not have access or timely access to Mohs, so they would likely proceed with standard wide local excision. Otherwise, if there is the capability to perform Mohs, it would be preferred," he added.

"There is no benefit to a standard excision over Mohs," Rohrer emphasized. "If a surgeon is not sure if they have attained clear margins, they could and often do take a little more tissue to be certain."

Also asked to comment on the data, Chad L. Prather, MD, a dermatologist in Baton Rouge, Louisiana, said, "we know that Mohs has been used for cancers that are not highly staged and we know it's better than WLE, but this study shows that it is beneficial for higher stage cancers."

However, he cautioned that unlike early-stage cancers, where Mohs is usually a definitive treatment, with higher stage disease it is a starting point. "As a takeaway, Mohs is superior, but it needs to be followed through," he said. "These patients need to be closely followed as they are at a high risk for recurrence and metastasis and may need to be worked up for lymph node involvement and need additional therapy going forward."

Prather also pointed out that there are circumstances when WLE may be a more suitable treatment. "Mohs is not very good if there is bony involvement," he said. "This most often happens when the lesion is on the scalp and has invaded the skull. WLE may still be the preferred choice."

Additionally, Mohs is not the best choice if the tumor is broken into multiple segments. "In these cases, WLE may be preferred," Prather added. "But overall, Mohs is one of the best tools we have, and it stands to reason that it works well for high-risk tumors, as this study shows."

The study was independently supported. Wang reported no relevant financial relationships. Rohrer and Prather had no relevant disclosures.

Roxanne Nelson is a registered nurse and an award-winning medical writer who has written for many major news outlets and is a regular contributor to Medscape Medical News.