What Is the Demicco Risk Score for Solitary Fibrous Tumor?

The Demicco risk score is the standard tool doctors use to predict the likelihood that a solitary fibrous tumor (SFT) will spread (metastasize) to other parts of the body ^[1]. Based on specific details found in your tumor’s pathology report, the system assigns points to different characteristics to calculate a total score ^[2]. This score classifies your tumor as low, intermediate, or high risk, which helps your care team decide how closely they need to monitor you in the years following surgery ^[3].

Because SFTs are rare, it is often recommended to have your pathology report reviewed by a sarcoma specialist to ensure your score is calculated accurately.

The Four Key Variables

Pathologists look at specific features of your tumor under a microscope to determine your score. The modern “updated” Demicco score evaluates four variables ^[2]:

• Patient Age: Your age at the time of diagnosis. Being 55 years or older adds a point to the risk score ^[3].
• Tumor Size: The maximum measurement of the tumor in centimeters (cm). Larger tumors receive more points ^[4].
• Mitotic Count: A measure of how fast the tumor cells are dividing. Pathologists count the number of actively dividing cells (mitoses) in a specific area under the microscope ^[5]. This is traditionally reported as “per 10 high-power fields (HPF)” ^[6]. Note: Modern pathology reports may report this in “millimeters squared ($mm^2$)” as standards change, so you might see either measurement.
• Tumor Necrosis: The presence of dead tumor tissue. This sounds alarming, but it is a common and expected occurrence; when a tumor grows quickly, it can sometimes outgrow its blood supply, causing parts of the tissue to die ^[3]. Having tumor necrosis adds a point to the risk score ^[2].

How the Score is Calculated

You might encounter two versions of the Demicco score in your medical records. The original 2012 model used only age, size, and mitotic count (a 3-variable system) ^[7]. In 2017, the model was updated to include necrosis (a 4-variable system) because adding this feature proved to be more accurate at predicting how the tumor will behave ^[3].

In the updated 2017 model, points are assigned as follows:

(Note: If a feature is below these minimum thresholds—for example, you are under 55 or the tumor is less than 5 cm—it receives 0 points ^[3].)

What the Risk Categories Mean

The points from the table above are added together for a total score ranging from 0 to 7 ^[3]. This total places the tumor into one of three risk categories:

• Low Risk (0 to 3 points): The tumor has a very low chance of spreading. Studies show patients in this category have an extremely high chance (often approaching 100%) of remaining metastasis-free for 10 years or more ^[3].
• Intermediate Risk (4 to 5 points): There is a moderate risk of the tumor returning or spreading. Studies suggest a 20% to 30% risk of metastasis at 10 years ^[3]. Your doctor will likely recommend regular imaging scans to monitor you so that any changes can be caught early.
• High Risk (6 to 7 points): The tumor has a higher chance of spreading to other organs, such as the lungs, liver, or bones ^[8]. Studies indicate this group has roughly a 73% risk of metastasis within 5 years ^[3]. It is very important to remember that these are population statistics, not guarantees about your individual outcome. If metastasis does occur, treatments like surgery, radiation, or targeted therapies are available to help manage it. Your medical team will recommend a proactive monitoring schedule and will discuss whether any additional treatments are appropriate right now.

A Note on Tumor Location

It is important to know that the Demicco risk score was developed and validated for SFTs located in the body, such as the chest, abdomen, or limbs ^[9]. If your SFT is located in the central nervous system (inside the brain or spinal cord), the Demicco score is not considered an accurate predictor of how your tumor will behave ^[10]. For brain and spinal tumors, doctors rely more heavily on the World Health Organization (WHO) grading system instead ^[9].