New Evidence Published Supporting Use of DecisionDx®-SCC Test in Guiding and Improving Treatment Pathway Decisions in NCCN High-Risk Cutaneous Squamous Cell Carcinoma
Castle Biosciences (Nasdaq: CSTL) announced the publication of two significant studies validating their DecisionDx-SCC test for high-risk cutaneous squamous cell carcinoma (SCC). The first study demonstrated the test's ability to predict local recurrence in National Comprehensive Cancer Network (NCCN) high-risk patients post-Mohs surgery, adding to its existing capabilities of predicting metastasis risk and response to adjuvant radiation therapy (ART).
The studies showed that DecisionDx-SCC significantly outperformed traditional staging systems, with three-year local recurrence-free survival rates of 95.3% (Class 1), 85.5% (Class 2A), and 71.4% (Class 2B). The test demonstrated superior predictive accuracy when combined with clinicopathologic factors, providing clinicians with actionable decision points for treatment planning.
Castle Biosciences (Nasdaq: CSTL) ha pubblicato due studi importanti che convalidano il loro test DecisionDx-SCC per il carcinoma squamoso cutaneo (SCC) ad alto rischio. Il primo studio ha mostrato la capacità del test di prevedere la recidiva locale nei pazienti ad alto rischio secondo le linee guida NCCN dopo intervento di Mohs, aggiungendo questa funzione alle sue già note capacità di prevedere il rischio di metastasi e la risposta alla radioterapia adiuvante (ART).
Gli studi hanno evidenziato che il DecisionDx-SCC supera significativamente i sistemi di stadiazione tradizionali, con tassi di sopravvivenza senza recidiva locale a tre anni pari al 95,3% (Classe 1), 85,5% (Classe 2A) e 71,4% (Classe 2B). Il test ha mostrato una maggiore accuratezza predittiva se utilizzato insieme a fattori clinicopatologici, offrendo ai clinici punti decisionali utili per la pianificazione terapeutica.
Castle Biosciences (Nasdaq: CSTL) anunció la publicación de dos estudios importantes que validan su prueba DecisionDx-SCC para el carcinoma de células escamosas cutáneo (SCC) de alto riesgo. El primer estudio demostró la capacidad de la prueba para predecir la recurrencia local en pacientes de alto riesgo según la NCCN tras cirugía de Mohs, sumándose a sus ya documentadas capacidades para predecir el riesgo de metástasis y la respuesta a la radioterapia adyuvante (ART).
Los estudios mostraron que el DecisionDx-SCC superó significativamente a los sistemas de estadificación tradicionales, con tasas de supervivencia libre de recurrencia local a tres años del 95,3% (Clase 1), 85,5% (Clase 2A) y 71,4% (Clase 2B). La prueba demostró una mayor precisión predictiva cuando se combinó con factores clinicopatológicos, proporcionando a los clínicos puntos de decisión prácticos para la planificación del tratamiento.
Castle Biosciences (Nasdaq: CSTL)는 고위험 피부 편평세포암(SCC)에 대한 자사의 DecisionDx-SCC 검사를 검증한 두 건의 주요 연구를 발표했습니다. 첫 번째 연구는 Mohs 수술 후 NCCN 고위험 환자에서 검사로 국소 재발을 예측할 수 있음을 보여주었으며, 이는 전이 위험 및 보조 방사선치료(ART)에 대한 반응 예측 능력에 더해진 결과입니다.
연구 결과 DecisionDx-SCC는 전통적인 병기 분류보다 유의미하게 우수했으며, 3년 국소 재발 무병 생존율은 클래스 1이 95.3%, 클래스 2A가 85.5%, 클래스 2B가 71.4%로 나타났습니다. 이 검사는 임상병리학적 요인과 함께 사용했을 때 예측력이 향상되어 임상의가 치료 계획을 세우는 데 실질적인 판단 근거를 제공했습니다.
Castle Biosciences (Nasdaq: CSTL) a annoncé la publication de deux études importantes validant leur test DecisionDx-SCC pour le carcinome épidermoïde cutané (SCC) à haut risque. La première étude a montré la capacité du test à prédire la récidive locale chez des patients à haut risque selon la NCCN après une chirurgie de Mohs, s'ajoutant à ses capacités déjà établies de prédire le risque de métastases et la réponse à la radiothérapie adjuvante (ART).
Les études ont révélé que le DecisionDx-SCC surpasse nettement les systèmes de stadification traditionnels, avec des taux de survie sans récidive locale à trois ans de 95,3% (Classe 1), 85,5% (Classe 2A) et 71,4% (Classe 2B). Le test a montré une précision prédictive supérieure lorsqu'il est combiné à des facteurs clinicopathologiques, offrant aux cliniciens des points de décision opérationnels pour la planification des traitements.
Castle Biosciences (Nasdaq: CSTL) hat die Veröffentlichung von zwei bedeutenden Studien bekanntgegeben, die ihren DecisionDx-SCC-Test für hochrisikobehaftetes kutanes Plattenepithelkarzinom (SCC) validieren. Die erste Studie zeigte, dass der Test lokale Rezidive bei NCCN-Hochrisikopatienten nach Mohs-Chirurgie vorhersagen kann und ergänzt damit seine bereits belegten Fähigkeiten zur Vorhersage von Metastasierungsrisiko und zur Reaktion auf adjuvante Strahlentherapie (ART).
Die Studien belegten, dass DecisionDx-SCC die traditionellen Stadieneinteilungen deutlich übertrifft, mit dreijährigen rezidivfreien Überlebensraten von 95,3% (Klasse 1), 85,5% (Klasse 2A) und 71,4% (Klasse 2B). Kombiniert mit klinisch-pathologischen Faktoren erzielte der Test eine bessere prädiktive Genauigkeit und liefert Kliniker:innen verwertbare Entscheidungsgrundlagen für die Therapieplanung.
- Test successfully predicts three critical factors: metastasis risk, radiation therapy response, and local recurrence risk
- Demonstrated significant improvement in predictive accuracy compared to traditional staging systems
- Strong validation data from 414 NCCN high-risk SCC patients showing clear risk stratification
- Clinical survey confirms test results align with physician treatment decision thresholds
- Study indicates some high-risk patients may be currently under-treated while low-risk patients may be over-treated
Insights
Castle's DecisionDx-SCC test now validated to predict three critical outcomes in skin cancer patients, potentially expanding market adoption and clinical utility.
Castle Biosciences has achieved a significant clinical milestone with the publication of two new validation studies for their DecisionDx-SCC genomic test. The most notable advancement is the expansion of the test's capabilities to now predict three distinct outcomes in high-risk cutaneous squamous cell carcinoma (SCC) patients: metastasis risk, response to adjuvant radiation therapy, and now local recurrence.
What makes this particularly valuable is that the test significantly outperformed established staging systems (AJCC and BWH) in stratifying both local recurrence and metastatic risk in patients with NCCN high-risk SCC who had undergone Mohs surgery. The three-year survival rates showed clear stratification across risk classes, with local recurrence-free survival rates of
The second study demonstrates clinical utility, showing that the test's risk classifications align effectively with physician decision thresholds. Most surveyed clinicians recommended adjuvant radiation therapy for patients with ≥
This evidence positions Castle's test as a potentially practice-changing tool that addresses a critical clinical gap in risk stratification. Current staging systems often lead to overtreatment of low-risk patients and undertreatment of high-risk ones. By providing individualized risk assessment based on tumor biology rather than population-based criteria, the test enables physicians to better tailor post-surgical management and treatment pathways, potentially improving patient outcomes while optimizing healthcare resource utilization.
New validation study shows DecisionDx-SCC significantly outperforms current staging systems in predicting risk of local recurrence and metastasis for NCCN high-risk patients
Clinician survey confirms test results align with treatment decision-making thresholds for adjuvant radiation therapy and surveillance imaging
FRIENDSWOOD, Texas, Aug. 25, 2025 (GLOBE NEWSWIRE) -- Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced the publication of two new studies related to its DecisionDx-SCC test, adding to its validated uses for patients with high-risk cutaneous squamous cell carcinoma (SCC).1,2 DecisionDx-SCC is a gene expression profile test (40-GEP) designed to use a patient’s tumor biology to predict individual risk of metastasis as well as response to adjuvant radiation therapy (ART).
The first study represents an expanded clinical use milestone, demonstrating that DecisionDx-SCC predicts local recurrence in patients classified as high-risk by National Comprehensive Cancer Network (NCCN) guidelines who have undergone Mohs resection, thereby adding a third use to the test's existing capabilities.¹ The test has now been shown to predict individual risk of metastasis, response to ART and individual risk of local recurrence, providing comprehensive results to support tailored post-surgical management and treatment pathway recommendations for patients with SCC. The second study shares results from a clinician survey, affirming the impact of the test’s results in guiding these recommendations, specifically the use of ART and surveillance imaging, by providing actionable decision points based on individual patient risk.2
“These new data indicate that DecisionDx-SCC test results provide individualized risk predictions that doctors can use to guide risk-aligned escalation or de-escalation of care in their NCCN high-risk SCC patients,” said Désirée Ratner, M.D., Mohs micrographic surgeon and clinical professor of dermatology at the NYU Grossman School of Medicine in New York. “The ability of the test to reliably identify those patients with NCCN high-risk SCC at risk of developing local recurrence or metastasis is not only practice-changing for physicians who treat SCC, but also life-changing for their patients.”
While most patients with NCCN high-risk SCC can be treated successfully with Mohs surgery, a subset of these patients will experience local recurrence and/or metastasis. Current staging systems, including American Joint Committee on Cancer (AJCC) version 8 staging and Brigham and Women’s Hospital (BWH) T-staging, inadequately identify which patients are at highest risk for poor outcomes, creating a critical clinical need for better risk stratification tools. This limitation makes it challenging for clinicians to determine optimal treatment strategies, leading to over-treatment of low-risk patients and under-treatment of high-risk patients who may benefit from escalated approaches such as ART or enhanced post-surgical surveillance. These two new studies contribute to growing evidence that DecisionDx-SCC has the potential to address this clinical gap by enabling risk-aligned treatment decisions based on a patient’s individual tumor biology rather than population-based staging criteria alone.
Key highlights of the studies include the following:
- Among 414 NCCN high-risk SCC patients with negative margins following Mohs surgery, DecisionDx-SCC significantly stratified both local recurrence and metastatic risk. Three-year survival rates decreased progressively across risk classes: local recurrence-free survival (LRFS) was
95.3% (Class 1, low risk) vs.85.5% (Class 2A, higher risk) vs.71.4% (Class 2B, highest risk), P=0.001; metastasis-free survival (MFS) was97.1% vs.89.3% vs.57.1% , P<0.001. - In contrast, BWH and AJCC staging systems failed to significantly stratify LRFS (log-rank, P=0.6) and MFS (log-rank, P=0.8).1
- DecisionDx-SCC test results (Class 2A and 2B), immunosuppression and perineural invasion were significant predictors of local recurrence, with hazard ratios of 2.6, 5.3, 2.3 and 3.7, respectively (all P<0.05). When combined with these two clinicopathologic factors which have a well-established association to a high risk of metastasis, DecisionDx-SCC demonstrated significant improvement in predictive accuracy compared to the clinicopathologic factors alone (likelihood ratio: 21.65 vs. 12.27).¹
- The 244 clinicians surveyed in the second study most often recommended ART for patients with ≥
20% risk of local recurrence or metastasis, and surveillance imaging for patients with ≥10% risk of metastasis.2 - Accordingly, DecisionDx-SCC Class 2A results accurately predicted risk above the
10% threshold where most clinicians would recommend surveillance imaging and consider ART, while Class 2B results predicted risk above the20% threshold where most clinicians would recommend proceeding with ART.1,2 - Clinicians who use DecisionDx-SCC reported a Class 2B test result to be among the most important risk factors they consider when making management decisions for ART.2
Together, these studies provide compelling support for the use of DecisionDx-SCC in clinical practice to precisely identify NCCN high-risk patients above and below established risk thresholds, enabling clinicians to better align treatment strategies with individual patient risk and potentially improving outcomes within established NCCN treatment pathways.
About DecisionDx-SCC
DecisionDx-SCC is a 40-gene expression profile test that uses an individual patient’s tumor biology to predict individual risk of cutaneous squamous cell carcinoma metastasis for patients with one or more risk factors. The test result, in which patients are stratified into a Class 1 (low), Class 2A (higher) or Class 2B (highest) risk category, predicts individual metastatic risk to inform risk-appropriate management. Peer-reviewed publications have demonstrated that DecisionDx-SCC is an independent predictor of metastatic risk and that integrating DecisionDx-SCC with current prognostic methods can add positive predictive value to clinician decisions regarding staging and management. Learn more at www.CastleBiosciences.com.
About Castle Biosciences
Castle Biosciences (Nasdaq: CSTL) is a leading diagnostics company improving health through innovative tests that guide patient care. The Company aims to transform disease management by keeping people first: patients, clinicians, employees and investors.
Castle’s current portfolio consists of tests for skin cancers, Barrett’s esophagus and uveal melanoma. Additionally, the Company has active research and development programs for tests in these and other diseases with high clinical need, including its test in development to help guide systemic therapy selection for patients with moderate-to-severe atopic dermatitis seeking biologic treatment. To learn more, please visit www.CastleBiosciences.com and connect with us on LinkedIn, Facebook, X and Instagram.
DecisionDx-Melanoma, DecisionDx-CMSeq, i31-SLNB, i31-ROR, DecisionDx-SCC, MyPath Melanoma, TissueCypher, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are trademarks of Castle Biosciences, Inc.
Forward-Looking Statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the “safe harbor” created by those sections. These forward-looking statements include, but are not limited to, statements concerning: the ability of DecisionDx-SCC to support improved, risk-aligned treatment pathway decisions; the significant prognostic capabilities of DecisionDx-SCC and its ability to (i) enhance risk stratification beyond traditional staging and (ii) equip clinicians with actionable results to enable more precise, personalized treatment decisions and optimize patient management and care. The words “believe,” “can” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements that we make. These forward-looking statements involve risks and uncertainties that could cause our actual results to differ materially from those in the forward-looking statements, including, without limitation: subsequent study or trial results and findings may contradict earlier study or trial results and findings or may not support the results obtained in these studies, including with respect to the discussion of our tests in this press release; actual application of our tests may not provide the aforementioned benefits to patients; and the risks set forth under the heading “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2024, and our Quarterly Report on Form 10-Q for the quarter ended June 30, 2025, each as filed with the SEC, and in our other filings with the SEC. The forward-looking statements are applicable only as of the date on which they are made, and we do not assume any obligation to update any forward-looking statements, except as may be required by law.
- Ratner D, Arron ST, Kim YJ, et al. The 40-Gene Expression Profile Test Identifies Patients with National Comprehensive Cancer Network High-Risk Cutaneous Squamous Cell Carcinoma at High Risk of Poor Outcomes to Inform Management Decisions. J of Skin. 2025;9(4):2426-2443. doi:10.25251/mvr2rn83
- Shah M, Zakria D, Rogers JH, et al. Actionable Risk Thresholds for Adjuvant Radiation Therapy and Surveillance Imaging in High-Risk Cutaneous Squamous Cell Carcinoma. J of Skin. 2025;9(4):2444-2461. doi:10.25251/83v2hr07
Investor Contact:
Camilla Zuckero
czuckero@castlebiosciences.com
Media Contact:
Allison Marshall
amarshall@castlebiosciences.com
Source: Castle Biosciences, Inc.
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