DecisionDx®-SCC Significantly Improves Prediction Accuracy of Metastatic Events after Mohs Surgery in New Study of Patients with High-Risk Cutaneous Squamous Cell Carcinoma Tumors of the Head and Neck

Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced that new data supporting the utility of its DecisionDx-SCC test in patients with high-risk cutaneous squamous cell carcinoma (SCC) tumors located on the head and neck (H&N) will be shared at the 56th American College of Mohs Surgery (ACMS) Annual Meeting, being held May 2-5 in Phoenix.

“Mohs surgery is commonly used to remove high-risk SCC tumors located on a patient’s head or neck and is the best method to ensure complete removal of the tumor,” said Sherrif Ibrahim, M.D., Ph.D., lead study author and board-certified Mohs micrographic surgeon and dermatologist at Rochester Dermatologic Surgery in Victor, New York. “In most cases, once a tumor is removed completely, the patient is in the clear. However, aggressive SCC tumors may still return in the same location from which they were removed or worse, spread to other parts of the body, posing a very serious health risk to patients.

“The data being presented at ACMS show the power of DecisionDx-SCC to identify these high-risk patients, enabling more risk-appropriate surveillance or adjuvant treatments to help reduce the patient’s risk of these events occurring.”

Details regarding Castle’s poster at ACMS are included below:

• Title: Addition of the 40-gene expression profile (40-GEP) test in risk assessment improves prognostic accuracy and risk stratification for high-risk cutaneous squamous cell carcinoma (HR-cSCC) of the head and neck successfully treated with Mohs micrographic surgery (MMS)
• Poster Number: Poster 21
• First and Presenting Author: Sherrif Ibrahim, M.D., Ph.D.
• Location: Valley of the Sun Ballroom foyer (2nd floor), Sheraton Phoenix Downtown
• Summary: Despite reported definitive, clear tumor margins, 5-8% of patients with high-risk SCC treated with Mohs surgery will still develop metastasis. This study included 417 patients who received definitive Mohs surgery to remove high-risk SCC tumors of the H&N with reported clear margins. DecisionDx-SCC testing of the tumor tissue before removal significantly increased the prediction accuracy of metastatic events, when used alone and when combined with National Comprehensive Cancer Network (NCCN) guidelines, Brigham and Women’s Hospital (BWH) staging or American Joint Committee on Cancer Staging Manual, 8th Edition (AJCC8) staging, to better guide risk-aligned patient care decisions regarding metastatic surveillance or the use of adjuvant treatments like radiation.

Presenting authors will be available to answer questions regarding their posters on Saturday, May 4, from 12-1 p.m. Mountain Standard Time. Abstracts will also be in ACMS' CME & Abstract Book and available for online viewing via the Planstone abstract site.

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.

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, mental health conditions and uveal melanoma. Additionally, the Company has active research and development programs for tests in 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, psoriasis and related conditions. To learn more, please visit www.CastleBiosciences.com and connect with us on LinkedIn, Facebook, X and Instagram.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-SCC, MyPath Melanoma, DiffDx-Melanoma, TissueCypher, IDgenetix, 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 the DecisionDx-SCC test to identify high-risk patients and significantly increase the prediction accuracy of metastatic events, to better guide risk-aligned patient care decisions regarding metastatic surveillance or the use of adjuvant treatments like radiation. The words “can,” “potential” 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 recommendations and guidelines presented in this report, including with respect to the discussion of DecisionDx-SCC 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, 2023, 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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20240503767002/en/