NCCN 2026 Guidelines: BCC, SCC, DFSP & MCC for Mohs Surgeons
This article summarizes the NCCN 2025-2026 clinical practice guidelines for four cutaneous malignancies relevant to Mohs surgeons: basal cell carcinoma (BCC V1.2026), squamous cell carcinoma (SCC V2.2026), dermatofibrosarcoma protuberans (DFSP V2.2026), and Merkel cell carcinoma (MCC V2.2026). Key updates include the three-tier SCC risk stratification system, cemiplimab adjuvant approval for high-risk cSCC, and consolidation of Mohs/PDEMA as the preferred approach for DFSP. Each recommendation is paraphrased from published guideline versions and attributed to the NCCN source.
By Dr. Yehonatan Kaplan (M.D., Fellow ACMS)·Published: 2026-04-22·Updated: 2026-04-22·Reviewed: 2026-04-22
NCCN guidelinesBCCSCCDFSPMCCMohs surgeryrisk stratificationtreatment guidelines
Key Takeaways
- NCCN now classifies cutaneous SCC into three risk tiers (low, high, very high), validated in a 10,196-tumor study (PMID 37285135) showing the very high-risk group identifies tumors at greatest risk for poor outcomes.
- Mohs micrographic surgery or PDEMA is recommended for all high-risk BCC, all high-risk and very high-risk SCC, and all DFSP (preferred over wide excision).
- Cemiplimab received approval as adjuvant therapy for high-risk cSCC after surgery and radiation, with 24-month disease-free survival of 87.1% versus 64.1% for placebo (C-POST trial, PMID 40454639).
- The BWH staging system classifies only 5% of SCC as high-stage (T2b/T3), yet these tumors account for 60% of nodal metastases and 83% of disease-specific deaths (PMID 24366933).
- For DFSP, Mohs/PDEMA achieves local recurrence rates of 1-3% compared to 7-20% with wide local excision using 2-4 cm margins.
- All MCC patients with clinically node-negative disease should be offered sentinel lymph node biopsy per NCCN recommendations.
Overview & Guideline Versions
The NCCN publishes annually updated clinical practice guidelines for cutaneous malignancies that serve as the primary treatment reference for oncologists, dermatologic surgeons, and Mohs surgeons in the United States. The current versions relevant to Mohs practice are: Basal Cell Skin Cancer V1.2026 (released September 2025), Squamous Cell Skin Cancer V2.2026, Dermatofibrosarcoma Protuberans V2.2026, and Merkel Cell Carcinoma V2.2026. All four guidelines use a risk-stratification approach to determine treatment modality, and all four include Mohs micrographic surgery or PDEMA (peripheral and deep en face margin assessment) as a treatment option. For Mohs surgeons, the key updates across the 2025-2026 cycle include the now-validated three-tier SCC risk system, cemiplimab adjuvant approval for high-risk cSCC, and consolidated endorsement of Mohs as the preferred approach for DFSP. This article summarizes and interprets each guideline from the Mohs surgeon perspective. It does not reproduce guideline text verbatim. Full guidelines are available at NCCN.org with free clinician registration.
BCC Risk Stratification & Surgical Management
Per NCCN BCC V1.2026, basal cell carcinoma is stratified into low-risk and high-risk categories. The presence of any single high-risk feature qualifies the tumor for Mohs micrographic surgery or PDEMA. Low-risk BCC may be treated with standard excision using 4 mm clinical margins. The V1.2026 risk table uses anatomical descriptors rather than the H/M/L zone system: any BCC on the head, neck, hands, feet, pretibial region, or anogenital area is high-risk regardless of size. For trunk and extremity BCC, the size threshold is 2 cm (below 2 cm is low-risk, 2 cm or larger is high-risk). Additional high-risk features include poorly defined clinical borders, recurrent or incompletely excised tumors, immunosuppression, prior radiation at the site, and aggressive histologic subtypes (infiltrative, morpheaform, micronodular, basosquamous, sclerosing, and BCC with sarcomatoid differentiation). Perineural invasion on biopsy also qualifies as high-risk. For tumors under 6 mm in high-risk locations without other high-risk features, NCCN notes that alternative treatment modalities may be considered if at least 4 mm tumor-free margins can be obtained.
| Risk Domain | Low Risk | High Risk |
|---|---|---|
| Location / Size | Trunk, extremities <2 cm | Head, neck, hands, feet, pretibial, anogenital (any size); Trunk, extremities >=2 cm |
| Clinical borders | Well-defined | Poorly defined |
| Recurrence status | Primary tumor | Recurrent |
| Immune status | Immunocompetent | Immunosuppressed |
| Prior radiation | No prior RT at site | Prior RT at site |
| Histologic subtype | Nodular, superficial, keratotic, infundibulocystic, fibroepithelioma of Pinkus | Infiltrative, morpheaform, micronodular, basosquamous, sclerosing, sarcomatoid differentiation |
| Perineural invasion | Absent | Present |
| Recommended surgery | Standard excision 4 mm margins | Mohs/PDEMA recommended |
SCC Risk Stratification: Low, High, and Very High Risk
Starting with version 1.2022 (PMID 34902824), NCCN reclassified cutaneous squamous cell carcinoma into three risk tiers: low risk, high risk, and very high risk. This was a major departure from the previous two-tier system and represents one of the most significant changes to SCC management guidelines in the past decade. The three-tier system was designed to identify a subset of SCC tumors with the highest probability of adverse outcomes, allowing more targeted treatment and surveillance. A 2023 multicenter validation study by Ruiz et al. (PMID 37285135, n = 10,196 tumors) confirmed that the very high-risk tier identifies tumors at the greatest risk for local recurrence, nodal metastasis, distant metastasis, and disease-specific death. Per NCCN, Mohs micrographic surgery or PDEMA is the preferred surgical modality for both high-risk and very high-risk SCC. Low-risk SCC may be treated with standard excision using 4-6 mm margins. Per V1.2026, very high-risk SCC is defined by any of the following: tumor greater than 4 cm in any location, perineural invasion involving nerve sheath deeper than the dermis or nerves 0.1 mm or larger in caliber, depth greater than 6 mm or invasion beyond subcutaneous fat, lymphovascular invasion, or poorly differentiated/adenosquamous/sarcomatoid histologic subtypes in the context of other high-risk features.
| Feature | Low Risk | High Risk | Very High Risk |
|---|---|---|---|
| Location / Size | Trunk, extremities <2 cm | Trunk, extremities 2-4 cm; Head, neck, hands, feet, pretibial, anogenital (any size) | >4 cm any location |
| Borders | Well-defined | Poorly defined | Any |
| Recurrence | Primary | Recurrent | Any |
| Immunosuppression | No | Yes | Any |
| Prior RT / chronic inflammation | No | Yes | Any |
| Rapid growth | No | Yes | Any |
| Neurologic symptoms | No | Yes | Any |
| Differentiation | Well or moderately differentiated | Poorly differentiated | Any |
| Histologic subtype | Absent | Present (adenosquamous, sarcomatoid) | Present |
| Depth | <2 mm, no invasion beyond subQ fat | 2-6 mm, no invasion beyond subQ fat | >6 mm or invasion beyond subQ fat |
| PNI | Absent | Present | Nerve sheath involvement deeper than dermis or nerve >=0.1 mm caliber |
| LVI | Absent | Absent | Present |
| Recommended surgery | Excision 4-6 mm | Mohs/PDEMA (preferred) | Mohs/PDEMA (preferred) + multidisciplinary evaluation |
SCC: BWH Staging as Complementary Tool
While NCCN uses its own risk stratification, the Brigham and Womens Hospital (BWH) staging system remains a valuable complementary prognostic tool for cutaneous SCC. BWH classifies SCC using four independent risk factors: tumor diameter 2 cm or larger, poor differentiation, perineural invasion of nerves 0.1 mm or larger in caliber, and tumor invasion beyond subcutaneous fat. Each factor present adds one point, generating stages T1 (0 factors), T2a (1 factor), T2b (2-3 factors), and T3 (4 factors). The power of BWH staging is its ability to concentrate risk: in the original validation cohort (PMID 24366933), only 5% of SCC tumors were classified as high-stage (T2b or T3), yet those 5% accounted for 60% of all nodal metastases and 83% of disease-specific deaths. BWH staging and NCCN risk tiers are not interchangeable but are complementary. A tumor classified as NCCN "very high risk" will typically be BWH T2b or T3. Using both systems together provides the most complete prognostic picture and helps identify which patients need the most aggressive surveillance and adjuvant therapy. For a detailed BWH staging table and discussion, see the tumor-scc article.
DFSP: Mohs as Preferred Treatment
NCCN DFSP guidelines (Version 2.2026; the first standalone JNCCN Insights article for DFSP was published as Version 1.2025, PMID 39819674) recommend Mohs micrographic surgery or PDEMA as the preferred surgical approach for both primary and recurrent DFSP. This is one of the strongest Mohs endorsements in any NCCN tumor guideline. The rationale is that DFSP has extensive, irregular subclinical extensions that make clinical margin estimation unreliable. Mohs/PDEMA provides 100% peripheral and deep margin evaluation, yielding local recurrence rates of approximately 1-3% compared to 7-20% with standard wide excision. When Mohs or PDEMA is unavailable, NCCN recommends wide local excision with 2-4 cm clinical margins extending to and including the investing fascia. Margins must be histologically negative. If positive margins are found on wide excision, re-excision is recommended. When Mohs or PDEMA achieves negative margins, adjuvant radiation is generally not needed. For unresectable, recurrent, or metastatic DFSP harboring the COL1A1::PDGFB fusion, imatinib mesylate (a tyrosine kinase inhibitor targeting the PDGF-beta receptor) is the systemic treatment option, with response rates of approximately 50-70%.
| Parameter | Mohs/PDEMA | Wide Local Excision |
|---|---|---|
| NCCN designation | Preferred / recommended | Alternative when Mohs unavailable |
| Margin assessment | 100% peripheral and deep (en face) | Sampling only (bread-loaf, approximately 1-2%) |
| Clinical margins | Variable (complete clearance) | 2-4 cm to investing fascia |
| Local recurrence | Approximately 1-3% | Approximately 7-20% |
| Tissue conservation | Superior | Large defects from predetermined margins |
| Adjuvant RT after clear margins | Not recommended | Not recommended |
MCC: Surgery and Immunotherapy
Per NCCN MCC guidelines (Version 2.2026; Insights article Version 1.2024, PMID 38244274), the management of Merkel cell carcinoma combines surgery with immunotherapy for advanced disease. For the primary tumor, NCCN recommends wide excision with 1-2 cm margins when feasible. Mohs micrographic surgery or PDEMA may be considered, particularly in anatomically constrained areas where tissue conservation is important. Sentinel lymph node biopsy (SLNB) is recommended for all patients with clinically node-negative MCC, regardless of tumor size, given the high rate of occult nodal metastasis. The major shift in MCC management over the past several years has been the integration of immune checkpoint inhibitors. PD-1 pathway inhibitors including avelumab and pembrolizumab achieve objective response rates of 50-70% as first-line therapy for advanced (unresectable or metastatic) MCC, with 3-year overall survival of approximately 64% in responders. This is a dramatic improvement over historical chemotherapy regimens, which produced response rates of 30-60% but with median durations of only 3-8 months and 3-year overall survival of approximately 10%. Immunotherapy has largely replaced chemotherapy as first-line systemic treatment for advanced MCC.
Mohs Surgery Indications Across Tumor Types (Summary)
The following table consolidates NCCN Mohs/PDEMA indications across all four cutaneous malignancy guidelines covered in this article. The strength of the Mohs recommendation varies by tumor type, from "preferred" (DFSP) to "may be considered" (MCC). For BCC and SCC, the key determinant is the NCCN risk category. For DFSP, Mohs is recommended for all cases regardless of other features. For MCC, the decision to use Mohs depends on anatomic constraints and the broader systemic management plan.
| Tumor | When Mohs/PDEMA Indicated | Margin if Standard Excision | Key Guideline Version |
|---|---|---|---|
| BCC | Any high-risk feature (head/neck/hands/feet/pretibial/anogenital any size, trunk/ext >=2 cm, aggressive subtype, recurrent, PNI) | 4 mm for low-risk | V1.2026 |
| SCC | High-risk or very high-risk tier | 4-6 mm for low-risk | V2.2026 |
| DFSP | All cases (preferred over wide excision) | 2-4 cm wide excision to fascia | V2.2026 |
| MCC | May be considered (especially for tissue conservation) | 1-2 cm wide excision | V2.2026 |
Key Updates for 2025-2026
Several significant updates occurred across the 2025-2026 NCCN guideline cycle that directly affect Mohs surgical practice. For SCC, cemiplimab (a PD-1 inhibitor) was approved as adjuvant therapy for high-risk cutaneous SCC after surgery and radiation. The C-POST trial (PMID 40454639) demonstrated 24-month disease-free survival of 87.1% with cemiplimab versus 64.1% with placebo. This is the first approved adjuvant immunotherapy for cSCC. For BCC, hedgehog pathway inhibitors (vismodegib and sonidegib) are increasingly used in the neoadjuvant setting before Mohs for locally advanced disease. Approximately 22% of ACMS members report using hedgehog inhibitors preoperatively to reduce tumor burden before surgery. For DFSP, version 1.2025 (PMID 39819674) was published as the first standalone JNCCN Insights article for this tumor type, formally consolidating Mohs/PDEMA as the preferred surgical approach. For MCC, immunotherapy integration into earlier treatment lines continues to evolve, with ongoing trials evaluating neoadjuvant checkpoint inhibitors before surgery.
Appropriate Use Criteria & NCCN Alignment
The 2012 AAD/ACMS/ASDSA/ASMS Appropriate Use Criteria for Mohs micrographic surgery (AUC, PMID 22958088) remain the standard reference for documenting Mohs appropriateness in the United States. The AUC scores largely align with NCCN high-risk criteria for BCC and SCC. When NCCN classifies a tumor as high-risk, the corresponding AUC score is typically 7-9 (appropriate). This alignment is not coincidental; both systems draw on the same evidence base for identifying tumors that benefit from complete margin assessment. For insurance documentation, surgeons should cite both the NCCN risk category and the AUC score. A note stating "This BCC is high-risk per NCCN V1.2026 (nose — head/neck location, infiltrative subtype) with an AUC score of 9 (appropriate)" provides the strongest documentation for medical necessity. The AUC evaluator tool on this site (/auc) automates this scoring process.
Internal Resources & Disclaimer
MohsPedia provides detailed articles on each tumor type covered in these guidelines. For in-depth discussion of histologic subtypes, immunohistochemistry markers, reconstruction considerations, and management algorithms, see the related articles: tumor-bcc (detailed BCC article), tumor-scc (detailed SCC article with BWH staging tables), tumor-dfsp (DFSP management and surgical technique), tumor-mcc (MCC management including immunotherapy), mohs-technique (Mohs surgical technique), and systemic-therapy-radiation (systemic treatments and radiation therapy). The Clinical Tools section includes an interactive AUC evaluator (/auc), NCCN risk stratification tool (/risk), and BWH staging calculator, each aligned with the current guideline recommendations. This article is a summary and interpretation of published NCCN guidelines and does not replace reading the full guideline documents. NCCN guidelines are copyrighted by the National Comprehensive Cancer Network and available at NCCN.org. All clinical decisions remain the responsibility of the treating physician.
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References
- [1]Schmults CD, Blitzblau R, Aasi SZ, Alam M, Andersen JS, Baumann BC, et al. NCCN Guidelines Insights: Squamous Cell Skin Cancer, Version 2.2024. J Natl Compr Canc Netw. 2023. doi:10.6004/jnccn.2023.0046 PMID: 37935106
- [2]Schmults CD, Blitzblau R, Aasi SZ, Alam M, Andersen JS, Baumann BC, et al. NCCN Guidelines Insights: Squamous Cell Skin Cancer, Version 1.2022. J Natl Compr Canc Netw. 2021. doi:10.6004/jnccn.2021.0059 PMID: 34902824
- [3]Ruiz ES, Kus KJB, Guo D, Kastrinos A, Zhong TH, Schmults CD, et al. Validation of the NCCN very high-risk criteria for cutaneous squamous cell carcinoma. J Am Acad Dermatol. 2023. doi:10.1016/j.jaad.2023.05.070 PMID: 37285135
- [4]Swanson EL, Aasi SZ, Alam M, Andersen JS, Baumann BC, Brewer JD, et al. NCCN Guidelines Insights: Dermatofibrosarcoma Protuberans, Version 1.2025. J Natl Compr Canc Netw. 2025. doi:10.6004/jnccn.2025.0002 PMID: 39819674
- [5]Nghiem P, Bichakjian CK, Bhatia S, Brownell I, Decker RH, Farma JM, et al. NCCN Guidelines Insights: Merkel Cell Carcinoma, Version 1.2024. J Natl Compr Canc Netw. 2024. doi:10.6004/jnccn.2024.0007 PMID: 38244274
- [6]Connolly SM, Baker DR, Coldiron BM, et al. AAD/ACMS/ASDSA/ASMS 2012 appropriate use criteria for Mohs micrographic surgery. J Am Acad Dermatol. 2012. doi:10.1016/j.jaad.2012.06.009 PMID: 22959232
- [7]Karia PS, Jambusaria-Pahlajani A, Harrington DP, et al. Evaluation of AJCC, IUAC, and BWH tumor staging for cutaneous squamous cell carcinoma. J Clin Oncol. 2014. PMID: 24366933
- [8]Hughes BGM, Mendoza RG, Herold S, Gutzmer R, Swanson N, Migden MR, et al. Cemiplimab as adjuvant treatment for patients with high-risk cutaneous squamous cell carcinoma (C-POST). Lancet. 2025. doi:10.1016/S0140-6736(25)00523-5 PMID: 40454639