Surgeon Reviews Options for Superficial Skin Cancer

ORLANDO, Fla. — Beyond appropriate use criteria for Mohs surgery outlined by a multidisciplinary ad hoc task force in 2012, choice of treatment for superficial skin cancers like basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in situ remains highly individualized, according to a Mohs surgeon who spoke at the American Academy of Dermatology (AAD) 2025 Annual Meeting.

Simply stated, “Mohs is not always the best option,” said Abigail H. Waldman, MD, medical director, Mohs and Dermatologic Surgery Center, at Brigham and Women’s Hospital, Boston.

Any one of many variables, such as prior treatments received, the status of the patient’s immune function, risk of bleeding, and the potential for less invasive options to reduce costs, might, together or individually, make one approach more attractive than another, but Waldman said there are no absolutes.

Risks, but Cure Rates Are High

With Mohs surgery, the cure rate for both superficial SCC and BCC lesions ranges from 98% to 99%, making resection attractive for “the very anxious patient who doesn’t want to think about their skin cancer anymore,” she said, but noted that all approaches have risks and benefits.

“There are complications,” she said, referring to the potential for hematomas, necrosis, infections, dehiscence, and scars. These are not the norm, but they cannot be overlooked for patients who are also candidates for a well-tolerated topical therapy.

At a symposium on March 9 at the AAD meeting, focused on “when to put down the scalpel,” Waldman reviewed the variables she employs to prioritize noninvasive therapies over Mohs surgery or the opposite.

In general, having any form of immunosuppression “bumps people up in treating small lesions with Mohs surgery,” but, again, every variable is considered within a larger context, according to Waldman. For example, multiple prior surgeries for SCC and BCC because of immunosuppression or a familial susceptibility might be the reason to consider other options if a nonsurgical approach is reasonable.

Yet, prior failure with topicals or other noninvasive therapies makes Mohs attractive.

“In my practice, I usually consider Mohs surgery in a patient who has already tried and failed a nonsurgical intervention,” Waldman said. “In my experience, that usually means that there is something else going on underneath.”

Despite still limited data, Waldman also said that she is more likely to consider Mohs surgery in patients with a history of graft vs host disease based on higher rates of failure in this group in a series of patients treated at Dana-Farber Cancer Institute, Boston, a center adjacent to her own in the Harvard health system.

Superficial tumors occurring in the context of extensive actinic damage; anatomical sites challenging to invasive interventions or to topical treatments, such as eyelids; and need for antiplatelet therapies or other blood thinners, are also included on a lengthy list of variables that Waldman raises when counseling patients about options.

Some Reasonable Topical Therapies Are Off-Label

When a topical approach is preferred and reasonable given adequate surveillance for recurrence, Waldman named several agents that have been available and commonly used for years, such as 5-fluorouracil (5-FU) and imiquimod. Alone or in combination, not all have an indication for superficial skin cancers, so it is comforting when supportive evidence becomes available.

One example is a recent retrospective analysis published in March by two collaborating centers documenting their experience with topical 5-FU and calcipotriene. Waldman said that although this combination is widely used, it remains an off-label approach.

“It is used for prophylaxis for actinic keratosis, but [for treatment] we have been using it for a little bit longer duration,” Waldman said. This involves application for a minimum of 5 days extended to 10 days in the absence of a reaction.

In the retrospective study, “there was a complete response in over 90% of superficial cancers if treated twice per day out of 10 days with a 2-year follow-up,” she said. Response rates have typically been higher for SCC relative to BCC, but she would consider this approach for either.

Cure rates reported for topical treatments of superficial skin cancers often have a broad range when evaluated across published studies, according to Waldman. She attributed the differences across studies to heterogeneity in patient selection, duration of therapy, use or nonuse of occlusion, and other factors.

Less enthusiastic about radiation for the treatment of superficial skin cancers, because of sometimes unpredictable long-term cosmetic results, the potential for changes in the skin to complicate subsequent surgery, and the cost of this treatment, Waldman also expressed some specific reservations about image-guided superficial radiation therapy (IG-SRT).

IG-SRT is not a new technology, but this has been more aggressively marketed recently by centers where this treatment is offered. Waldman said this technology is not always confined to superficial nonmelanoma lesions and is often delivered by clinicians not necessarily trained in therapeutic radiation.

In advertising, IG-SRT is often compared favorably with Mohs surgery, but she is concerned that this is misleading.

Although Widely Marketed, IG-SRT Remains Controversial

One issue with IG-SRT is that it can make margins more difficult to identify in the event of subsequent surgery. In addition, Waldman noted that one of the specific advantages of Mohs surgery is to evaluate each layer of tissue as it is excised, allowing for a more complete evaluation of the lesion and surrounding skin. She noted that it is not uncommon to uncover something unexpected during Mohs surgery, such as deeper penetration or vascular involvement, that results in doing something additional, like ordering imaging or adding an adjunctive treatment, such as radiation.

These steps “are not possible if you are not surgically evaluating the tumor,” Waldman said. “So I do worry about the 1%-5% of patients” for which there might be an opportunity for a more complete intervention.

While Waldman discussed other alternatives to Mohs surgery, including phototherapy and cryotherapy with curettage, the message was that this form of treatment despite its high cure rate and generally predictable healing, should be considered in the mix of approaches for patients with superficial skin cancers. She indicated that the best choice is typically reached in collaboration with a patient educated on the risks and benefits of competing options.

Asked to comment, Rebecca I. Hartman, MD, MPH, chief of Dermatology, VA Boston Healthcare System, Boston, who chaired and spoke at the same AAD symposium in which Waldman delivered her remarks, agreed that IG-SRT is “controversial.” Although she cited retrospective studies that have associated this approach with good outcomes, she is not aware of any head-to-head comparisons with Mohs surgery.

Citing an infographic issued by the American College of Mohs Surgery comparing the characteristics of Mohs surgery and IG-SRT, Hartman listed “known” disadvantages that include potential damage to healthy skin from radiation, the need for multiple treatments (15-20) to complete treatment, and the inability to confirm clear margins at the end of treatment.

However, Hartman acknowledged that she is not an expert in radiation and has never personally used IG-SRT. Unaware of any head-to-head trials comparing IG-SRT with Mohs surgery, definitive statements about relative risks and benefits are difficult, but IG-SRT is “not a first-line option” in her practice, even though she would not rule it out for patients with low-risk skin cancers who refused other options.

Waldman reported no potential conflicts of interest. Hartman reported financial relationships with Evereden, MJH Life Sciences, and Oasis Pharmaceuticals.