Diagnosing soft tissue sarcoma requires a careful approach because these cancers are rare and can be easily mistaken for many other types of growths. Getting the right diagnosis early helps doctors plan the best treatment and gives patients the best chance for recovery.
Introduction: Who Should Seek Diagnostics
Not every lump or bump in your body is a cause for concern, but certain signs should prompt you to see a doctor. If you notice a new lump anywhere on your body, especially one that seems to be growing, it’s important to get it checked out. Soft tissue sarcomas often don’t cause pain at first, which means you could have one for months or even years before you realize something is wrong.[1][2]
You should make an appointment with a healthcare provider if you notice a lump that starts to hurt, or if you have belly pain that keeps getting worse. Other warning signs include blood in your stool that makes it look black, nausea and vomiting without an obvious cause, or losing weight when you’re not trying to. These symptoms don’t automatically mean you have a sarcoma, but they do mean you need to see a doctor who can figure out what’s going on.[2]
Sometimes a sarcoma, which is a cancer that starts in the body’s soft tissues like muscle, fat, or blood vessels, appears as a painless lump under the skin, often on an arm or leg. Sarcomas that begin in the abdomen may not cause any signs or symptoms until they become very large and start pressing on nearby organs, nerves, muscles, or blood vessels. This is why regular check-ups are important, especially if you have any risk factors, which are things that increase your chance of developing the disease.[9]
Classic Diagnostic Methods
When you visit a doctor with concerns about a possible soft tissue sarcoma, they will start by asking about your symptoms and your medical history. They will want to know when you first noticed the lump, whether it has grown, and if you have any pain or other symptoms. The doctor will also ask about any past treatments you’ve had, such as radiation therapy, and whether anyone in your family has had cancer. This conversation helps the doctor understand your situation and decide what tests you might need.[2][10]
After talking with you, the doctor will do a physical exam. They will look at and feel any lumps or swelling you’ve noticed. They’ll check to see if the lump is firm or soft, whether it moves when you touch it, and if pressing on it causes pain. The doctor will also examine the rest of your body to look for other symptoms that might give clues about what’s happening.[2]
Imaging Tests
Once the physical exam is complete, your doctor will likely order imaging tests to get a better look at what’s inside your body. These tests create pictures that show the size and location of any unusual growths. The most common imaging tests for suspected soft tissue sarcoma include X-rays, which use radiation to create images of bones and some soft tissues. X-rays are often done first because they’re quick and readily available.[2][10]
A CT scan, also called a computed tomography scan, is a more detailed imaging test that uses X-rays taken from different angles to create cross-sectional images of your body. A computer then combines these images to show a 3D picture of your organs, bones, and soft tissues. CT scans can help doctors see the exact size and location of a tumor and whether it has spread to other areas.[2]
MRI, which stands for magnetic resonance imaging, uses powerful magnets and radio waves instead of radiation to create detailed pictures of soft tissues. MRI scans are especially useful for looking at soft tissue sarcomas because they show muscles, fat, blood vessels, and other soft structures very clearly. Doctors often prefer MRI scans for planning surgery because they provide such detailed information about the tumor and the tissues around it.[2][10]
A PET scan, short for positron emission tomography scan, is sometimes used to see if cancer has spread to other parts of the body. This test involves injecting a small amount of radioactive sugar into your bloodstream. Cancer cells tend to absorb more of this sugar than normal cells, so they show up as bright spots on the scan. PET scans can be helpful for finding cancer that has traveled to distant organs.[2][10]
Biopsy: The Definitive Test
Imaging tests can show that something unusual is present, but they cannot tell for certain whether a lump is cancer or what type of cancer it might be. To know for sure, doctors need to examine actual cells from the suspicious area. This is done through a procedure called a biopsy, which involves removing a small sample of tissue for testing in a laboratory.[9][10]
A biopsy for soft tissue sarcoma needs to be done very carefully because if it’s not performed correctly, it can make future surgery more difficult. For this reason, it’s strongly recommended that you have your biopsy done at a medical center that has experience treating soft tissue sarcomas. Experienced healthcare teams know how to take the tissue sample in a way that won’t interfere with later treatment.[10]
There are different types of biopsy procedures. A core needle biopsy uses a special needle to remove small cylinder-shaped samples of tissue from the tumor. Doctors usually try to take samples from several different parts of the growth to get a complete picture. This type of biopsy can often be done in a doctor’s office or outpatient clinic, and you typically go home the same day.[10]
In some cases, a surgical biopsy may be needed to get a larger tissue sample. During this procedure, a surgeon makes a cut in your skin and removes a piece of the suspicious tissue, or sometimes the entire lump if it’s small. Surgical biopsies are usually done when a needle biopsy doesn’t provide enough information or when the tumor is located in a place that’s hard to reach with a needle.[10]
After the biopsy sample is collected, it goes to a laboratory where specialists called pathologists examine it under a microscope. Pathologists are doctors who specialize in analyzing blood and body tissues to diagnose diseases. They look at the cells to see if they’re cancerous and, if so, what type of cancer cells they are. This information is crucial because different types of soft tissue sarcomas behave differently and require different treatments.[10]
The pathology report will include details about the type of sarcoma, how abnormal the cells look (called the grade), and other characteristics that help predict how aggressive the cancer might be. Sometimes additional tests are done on the biopsy sample to look for specific genetic changes or proteins that can guide treatment decisions. Getting an accurate pathology diagnosis is one of the most important steps in planning your care.[10]
Diagnostics for Clinical Trial Qualification
Clinical trials are research studies that test new treatments or combinations of treatments to see if they work better than current options. If you’re considering joining a clinical trial for soft tissue sarcoma, you’ll need to go through additional diagnostic tests to make sure you meet the specific requirements for that study. These requirements, called eligibility criteria, help researchers ensure that the trial participants are similar enough that the results will be meaningful and that the treatment being tested is safe for the people enrolled.[9]
Most clinical trials require confirmation of your diagnosis through a biopsy that has been reviewed by a pathologist. Some trials may even require that your tissue samples be sent to a central laboratory for additional testing to confirm the exact type and characteristics of your sarcoma. This extra level of review ensures that all participants in the trial truly have the type of cancer the study is designed to treat.[10]
You’ll typically need recent imaging tests to determine the stage of your cancer, which describes how large the tumor is and whether it has spread. Staging helps doctors understand how advanced the cancer is and plan appropriate treatment. For clinical trials, knowing the stage is crucial because many studies only accept patients whose cancer is at a certain stage. For example, some trials are designed for people with cancer that has spread to other parts of the body, while others are for people whose cancer is only in one area.[9]
Blood tests are another standard requirement for clinical trial enrollment. These tests check your overall health and how well your organs are functioning. They might include a complete blood count, which measures different types of cells in your blood, and tests of your kidney and liver function. Clinical trials need to know that your body is healthy enough to handle the treatment being studied and that you don’t have other medical conditions that might interfere with the research or put you at risk.[9]
Some clinical trials test treatments that target specific genetic changes or proteins in cancer cells. If you’re considering one of these trials, you may need additional specialized testing on your tumor tissue. For instance, your doctors might look for specific genetic mutations, which are changes in the DNA inside cancer cells, or they might test for certain proteins that the tumor produces. These tests help match patients to trials where the experimental treatment is most likely to help them.[10]
Performance status assessment is also commonly required for clinical trial participation. This is a measure of how well you’re able to carry out daily activities and how much the cancer is affecting your life. Doctors use standardized scales to rate your performance status, and many trials only accept patients who are still able to take care of themselves and be fairly active. This helps ensure that participants can tolerate the treatments being studied and complete the trial as planned.[13]
