How is Sarcoma Diagnosed?

Daniel Lerman, MD, Orthopedic Oncologist at the Institute for Limb Preservation at OrthoONE, a part of Sarah Cannon Cancer Institute at Presbyterian/St. Luke’s Medical Center in Denver, discusses what you should know about how sarcoma is diagnosed, including symptoms to be aware of and what to expect.

What are the signs and symptoms of sarcoma?

There are two broad categories for sarcoma. The first category is soft tissue sarcoma, which means that the cancer arises in the soft tissue elements of the extremity, such as muscles, fat, nerves and blood vessels. The second broad category is bone sarcoma, which are cancers that originate in the bone. Sarcomas are rare in adults, representing about 1% of all cancers.

The two categories of sarcoma present in different ways.

• Soft Tissue Sarcoma: The presentation is usually a painless, enlarging mass in the extremity. Like any process that is not painful, people may neglect it for many months, until enlargement becomes worrisome.
• Bone Sarcomas: Alternatively, bone sarcomas are typically painful, particularly at night while resting. It is believed that rest pain is due to increased pressure in the bone and irritation of the periosteum, the outer-most layer of the bone that contains nerve fibers. Pain that occurs at night and while resting is common for bone tumors that are growing. This is different from activity-related pain that more commonly represents a mechanical (non-oncologic) issue.

Soft tissue sarcomas are most common in the thigh, but can occur anywhere in the body where there is connective tissue, including the uterus, head, neck and lungs, and are not limited to the extremity. Bone sarcomas occur more commonly in the lower extremity.

Not every extremity mass is a cancer; in fact, most are benign.

What are the most common types of sarcoma?

• Soft Tissue Sarcoma: There are more than 60 subtypes of soft tissue sarcoma. The most common type is liposarcoma, which originates from fatty tissue.
• Bone Sarcomas: The most common type of bone sarcoma is osteosarcoma, which originates from the osteoblast (the bone cells themselves). Other common types are Ewing sarcoma and chondrosarcoma, the latter originating from cartilage cells.

The treatments for bone sarcomas are very much dependent on which subtype you have, and will vary widely. Alternatively, treatments for soft tissue sarcoma in the adult population are typically uniform, where surgery and radiation are routine with case-by-case consideration for chemotherapy.

Is there an age when I am more likely to get sarcoma?

The incidence of soft tissue sarcoma and bone sarcomas differ. The incidence of soft tissue sarcomas increases with age and is rare in younger populations. In contrast, bone sarcomas have a two peak incidences. The first peak is in adolescence and young adults around the age of 14-18, and the second peak is observed in patients in their 60’s.  

If I am experiencing symptoms worrisome for sarcoma, what should I do? What tests will my doctor perform?

There is not a meaningful blood test available for sarcomas. The best ways to evaluate sarcoma initially is by using imaging studies, typically starting with x-rays and then an MRI of the area of concern.

An orthopedic oncologist will use routine algorithms to evaluate abnormalities or lesions in the bone. It is important to follow those algorithms to ensure the greatest likelihood for an accurate diagnosis and treatment.

Above all, it is also important for people to have a confirmed diagnosis before undergoing a treatment. It is key for the doctor to know what makes up a lump or mass prior to surgical intervention because appropriate type of surgical treatment is based on the diagnosis. To establish a diagnosis, a tissue biopsy is often necessary.

If a person is experiencing extremity pain, many will first go to orthopedic surgeon, thinking that the mass is due to joint swelling. If there are concerning findings, it is important to see a doctor who specializes in extremity cancers, such as sarcomas.

How does a doctor diagnose sarcoma?

First, your doctor will diagnose the sarcoma, followed by staging and treatment. It is very important that all of these steps take place to help maximize the chances of an effective treatment.

If imaging studies are concerning, a tissue biopsy is often recommended. An interventional radiologist can perform a tissue biopsy with a needle in a minimally invasive manner. Alternatively, a surgeon can perform an open biopsy through a small incision in an operating room with the potential benefit of getting a larger specimen.

If the biopsy confirms a sarcoma diagnosis, staging must be completed in order to determine if the sarcoma is localized or if it has spread to other sites, as that will inform appropriate treatments.

What can I expect upon diagnosis?

Upon diagnosis, you can expect a thoughtful and comprehensive evaluation from a multidisciplinary care team, which should include a medical oncologist, a surgical oncologist, an orthopedic oncologist and a radiation oncologist.

Sarcoma cases are often complex and relatively rare, and should be managed at a center that specializes in sarcoma care with the all of the resources that you might need. This includes a multidisciplinary cancer conference, a sarcoma nurse navigator to help you through every step of the cancer journey and physical therapists who are familiar with the care of post-operative sarcoma patients in order to optimize outcomes. Because sarcomas occur in the upper and the lower extremities, physical outcomes are critical, and your care team wants to optimize your potential function following surgery.