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SRT vs Mohs: Why Patient Selection Matters Beyond Recurrence Rates

2026-09-16 16:21

Where Superficial Radiation Therapy Fits in Nonmelanoma Skin Cancer Care

A recent meta-analysis brings new evidence to the debate over superficial radiation therapy vs Mohs for nonmelanoma skin cancer, using local recurrence as the main comparison.

Published online in November 2025 and formally appearing in Dermatologic Surgery in 2026, the analysis pooled 9 SRT studies involving 7,809 cases and 17 Mohs studies involving 10,247 cases.

The pooled local recurrence rate was 6.3% for SRT and 1.9% for Mohs. [1]

The difference is clinically important, but its interpretation requires context.

These were not patients randomly assigned to SRT or Mohs in a single head-to-head trial. The meta-analysis combined separate studies that may have differed in tumor risk, patient selection, radiation technique, dose, clinical setting, and duration of follow-up.

The evidence supports a clear but carefully bounded conclusion: Mohs showed lower pooled local recurrence in the available literature.

It does not tell us that every patient with basal cell carcinoma or cutaneous squamous cell carcinoma should undergo Mohs, and it does not remove superficial radiation therapy from consideration when surgery is unsuitable or disproportionately burdensome.

What the 2026 Meta-Analysis Actually Found

The systematic review searched the literature through November 13, 2024 and included case series, cohort studies, chart reviews, and eligible randomized studies reporting outcomes after SRT and/or Mohs.

Using a random-effects model, the authors calculated:

Mohs micrographic surgery

Local recurrence: 1.9%
95% CI: 1.0%–2.9%

Superficial radiation therapy

Local recurrence: 6.3%
95% CI: 3.6%–9.6%

The authors concluded that local recurrence was lower after Mohs in the pooled literature. [1]

This result makes broad statements such as “SRT has recurrence or cure outcomes equivalent to Mohs” difficult to justify without substantial qualification.

It would be equally inaccurate to say that Mohs reduces every individual patient's recurrence risk from 6.3% to 1.9%. Those percentages came from different bodies of evidence rather than from identical patients randomized between the two treatments.

In practical terms, the current evidence favors Mohs for local control. SRT should not be presented as an interchangeable equivalent, although it remains clinically relevant when surgery is unsuitable or disproportionately burdensome.

Treatment choice still depends on tumor risk, anatomical site, patient health, surgical feasibility, and informed patient preference.

Where Mohs Has a Clear Advantage

Mohs micrographic surgery offers something superficial radiation therapy does not: microscopic margin assessment during the procedure.

Tissue is removed in stages and examined until the assessed margins are clear. This provides a high degree of margin control while preserving uninvolved tissue.

That combination can be particularly important when a tumor is recurrent, aggressive, poorly defined, or located in an area where tissue conservation matters.

AAD patient guidance notes that Mohs is commonly recommended when a BCC or SCC is aggressive or large, has recurred after previous treatment, or occurs at sites such as the eyelid, nose, ear, hand, or foot where tissue preservation can be especially important. [2]

Mohs may therefore be particularly relevant when:

the tumor has high-risk or aggressive features;
the lesion has recurred;
margins are poorly defined;
precise margin control is clinically important;
the anatomical site makes tissue preservation a priority;
the patient can reasonably tolerate surgery and any required repair.

Excellent local control, however, does not mean Mohs is necessary for every keratinocyte carcinoma.

AAD's Choosing Wisely recommendation specifically advises against routine Mohs for selected uncomplicated, small, low-risk BCC or SCC on the trunk and extremities in otherwise healthy patients. [3]

Tumor risk still comes first.

When Surgery Is Not the Best Fit

The treatment discussion changes when surgery becomes medically unsuitable or creates a disproportionate burden.

AAD guidance describes surgery as the cornerstone of BCC management. For cSCC, surgical treatment likewise remains the most effective general approach. Radiation and other nonsurgical therapies may be considered in selected disease or when surgery is contraindicated, with the understanding that local control may be lower. [4,5]

ASTRO also provides recommendations for definitive radiation therapy in appropriately selected basal and squamous cell cancers when a nonsurgical approach is clinically appropriate. [6]

Situations in which SRT may enter the discussion include patients with:

frailty or advanced age;
significant comorbidities;
limited ability to tolerate surgery;
concern about wound healing;
substantial reconstruction burden;
functional or cosmetic concerns associated with surgery;
a preference for a nonsurgical option after balanced counseling.

These are the clinical situations in which SRT becomes most relevant.

Its role does not depend on reproducing the margin-control advantages of Mohs. It offers a different treatment pathway for selected superficial disease when surgery is not the most appropriate or acceptable option.

For a broader look at when superficial X-ray radiotherapy can fit into dermatology practice, see our practical guide to SRT patient and clinic selection.

What SRT Changes for the Patient

The distinction between SRT and Mohs is not only about recurrence.

It also changes what treatment looks like for the patient.

SRT does not involve surgical excision. There is no operative wound, no sutured defect created by the treatment, and no surgical reconstruction simply because radiation is being delivered.

Treatment is generally outpatient, and patients leave after each session.

For some older or medically fragile patients, avoiding surgery and reconstruction can be meaningful. It may also reduce the short-term disruption associated with wound care, sutures, and postoperative healing.

That benefit still needs to be described accurately.

SRT should not be marketed as “painless” or “zero downtime.”

A course of superficial radiation usually requires repeated visits over days or weeks. Local reactions such as erythema, soreness, peeling, and radiation dermatitis can develop during treatment.

A more accurate description of the trade-off is:

SRT avoids a surgical wound and reconstruction, but requires a course of outpatient radiation and has its own local adverse-effect profile.

For one patient, that may fit daily life better than surgery and postoperative wound care.

For another, completing Mohs in a single surgical day may be more convenient than returning repeatedly for radiation.

Treatment burden is individual.

Superficial Radiation Therapy vs Mohs: A Clinical Comparison

Clinical question	Mohs micrographic surgery	Superficial radiation therapy
Local-control evidence	Lower pooled local recurrence in the 2026 meta-analysis: 1.9%	Higher pooled local recurrence in the same analysis: 6.3%
Margin assessment	Microscopic margin examination during surgery	No surgical margin examination
Surgical incision	Yes	No
Tumor removal	Surgical excision	No surgical excision
Reconstruction	May be required depending on the defect	No surgical reconstruction caused by treatment
Treatment schedule	Usually one surgical treatment day, followed by wound care and follow-up	Usually multiple outpatient treatment sessions
Recovery considerations	Surgical wound healing and possible reconstruction	No surgical wound; radiation skin reactions may occur
Particularly relevant when	Margin control, recurrence risk, and tissue conservation are major priorities	Surgery is unsuitable, disproportionately burdensome, or declined after informed discussion
Important limitation	Surgical and reconstruction burden	Higher pooled recurrence and repeated treatment visits

This table is a clinical overview, not a treatment algorithm.

BCC and cSCC vary widely in risk. Tumor size, depth, histology, anatomical site, recurrence status, previous therapy, perineural involvement, immune status, and other factors all influence management.

Patient Selection Matters on Both Sides

Patient selection is sometimes discussed as though it were mainly a concern for SRT.

It applies to Mohs as well.

A low-risk superficial lesion on the trunk of an otherwise healthy patient does not automatically require Mohs simply because Mohs offers excellent margin control. AAD explicitly cautions against routine Mohs in some small, uncomplicated, low-risk lesions. [3]

SRT likewise should not be offered simply because it is nonsurgical.

A 2023 publication proposed appropriate-use criteria for superficial radiation therapy in BCC and SCC, arguing for use within a defined clinical framework rather than indiscriminate application. [7]

“Non-surgical” is not itself an indication.

Neither is advanced age.

The tumor still needs to be suitable for superficial radiation. Risk category, depth, site, histology, previous treatment, and expected follow-up remain part of the decision.

A frail patient with a tumor poorly suited to superficial radiation does not become an appropriate SRT candidate simply because surgery would be difficult.

Why SRT and Mohs Are Not Interchangeable

Mohs and superficial radiation therapy may both appear in the management of nonmelanoma skin cancer, but they solve the problem differently.

Mohs is a surgical technique built around tumor removal and microscopic margin control.

SRT is a radiation modality that delivers ionizing radiation to superficial tissue over a prescribed treatment course.

For Mohs, the clinician obtains direct margin information during treatment.

SRT does not provide that information.

For SRT, the patient avoids excision and a surgical defect.

Mohs cannot offer that same nonsurgical treatment experience.

These differences are more clinically useful than describing one treatment as a surgical or nonsurgical version of the other.

The two approaches overlap in some patient populations, but they are not interchangeable.

What Patients Should Know Before Choosing SRT

A balanced discussion of SRT should include both favorable and unfavorable evidence.

Patients should understand that:

Mohs currently has stronger pooled local-control data;
the 6.3% versus 1.9% recurrence estimates do not come from a randomized head-to-head trial;
surgery remains an important treatment for many BCCs and cSCCs;
SRT generally requires multiple treatment sessions;
radiation-related skin reactions can occur;
long-term surveillance remains important;
SRT and image-guided SRT should not automatically be treated as identical evidence categories.

Recent literature on image-guided SRT has put additional emphasis on patient selection, transparency, training, resource stewardship, and potential conflicts of interest. A 2026 Journal of the American Academy of Dermatology publication focused specifically on those issues, while a separate Mayo Clinic commentary examined the ethical implications of recommending IGSRT directly in dermatopathology reports. [8,9]

Those discussions support a broader principle: evidence generated for one radiation technique, workflow, or platform should not automatically be transferred to another.

Patient preference also matters, but preference should follow an accurate explanation of the trade-offs.

A patient who strongly wants to avoid surgery may place considerable value on avoiding an incision and reconstruction.

Another may prioritize the strongest available local-control evidence and choose Mohs despite the surgical burden.

Both decisions require more information than a marketing claim.

What 'Superficial' Skin Cancer Actually Means for Treatment Choice

The word superficial can create false simplicity.

A superficial lesion is not automatically an SRT lesion.

It is not automatically a Mohs lesion either.

AAD specifically advises against routine Mohs for some uncomplicated, small, low-risk superficial BCCs or SCCs on the trunk and extremities. [3]

That does not mean superficial radiation automatically becomes the preferred alternative.

Standard excision, curettage, topical treatment in selected BCCs, radiation, or other approaches may be considered depending on diagnosis and risk.

The clinically relevant questions are more specific:

What is the tumor type?
Is it low or high risk?
How deep is it?
Where is it located?
Has it been treated before?
What treatment burden can the patient reasonably tolerate?

The word superficial is only one part of that assessment.

Where the Treatment Device Fits

Once superficial radiotherapy has been selected for an appropriate patient and lesion, a separate decision begins: how should the prescribed treatment be delivered?

Equipment becomes relevant at this stage.

A superficial X-ray system needs to support controlled radiation delivery, beam limitation, accurate positioning, stable output, safety controls, and a repeatable treatment workflow.

Treatment geometry and positioning are discussed in more detail in our guide to superficial radiotherapy positioning for skin cancer.

KernelMed's XT-5600 and XT-5601 belong at this point in the pathway: as treatment-delivery platforms after the clinical decision to use superficial radiotherapy has already been made.

Their role is not to determine whether SRT is preferable to Mohs.

Clinical outcomes depend on patient selection, tumor characteristics, treatment planning, dose, technique, and follow-up—not on the device alone.

The 6.3% SRT recurrence rate in the 2026 meta-analysis is literature-level pooled evidence and should not be interpreted as a clinical outcome for the XT-5600, XT-5601, or any other specific device without direct product-specific clinical evidence.

A Better Way to Discuss SRT and Mohs

The latest meta-analysis makes simple equivalence claims harder to defend.

Mohs has lower pooled local recurrence and remains especially important when margin control, recurrence risk, and tissue conservation are central to the case.

SRT has a different role. It becomes relevant when surgery is unsuitable, disproportionately burdensome, or declined after an informed discussion of the evidence and treatment trade-offs.

For clinics discussing superficial radiation with patients, transparent presentation of recurrence data, surgical alternatives, treatment burden, and patient-specific factors is more useful than claiming that the two approaches are equivalent.

Equipment selection comes after that clinical decision has been made.

FAQ

Is Mohs more effective than superficial radiation therapy?

The 2026 systematic review and meta-analysis found lower pooled local recurrence after Mohs: 1.9% compared with 6.3% after SRT. However, these rates came from different underlying studies rather than a randomized head-to-head trial, so they should not be interpreted as individual treatment probabilities for every patient. [1]

When might SRT be considered instead of surgery?

SRT may be considered for appropriately selected nonmelanoma skin cancers when surgery is contraindicated, poorly tolerated, likely to create disproportionate treatment burden, or declined after balanced counseling. Tumor type, risk, depth, location, and prior treatment still matter.

Is superficial radiation therapy painless?

SRT avoids a surgical incision, but calling it completely painless would be inaccurate. Radiation-related skin reactions such as erythema, soreness, and peeling can occur during the treatment course, and treatment usually requires multiple visits.

Is SRT a replacement for Mohs?

No. Mohs and SRT have overlapping but different clinical roles. Mohs provides microscopic margin control and currently has stronger pooled local-control data. SRT offers a nonsurgical option for selected patients when surgery is not the most appropriate or acceptable approach.

References

1. Patel JR, Engels E, Chinchilli E, Lambert Smith F.

Superficial Radiation Therapy versus Mohs Micrographic Surgery: A Systematic Review and Meta-Analysis.
Dermatologic Surgery. 2026;52(6):521–524.

https://pubmed.ncbi.nlm.nih.gov/41343548/