An NCI-designated Comprehensive Cancer Center
By Malcolm Bedell | July 31, 2019
Judith Sato Judith K. Sato, M.D.
Sarcomas are a relatively unusual type of cancer tumor that form in the bones or soft tissues of the body.
While sarcomas are most commonly found in the bones, muscles, tendons, cartilage, nerves, fat and blood vessels, they can occur almost anywhere. Sarcomas are somewhat rare; according to the American Cancer Society, there will be approximately 12,750 new soft tissue sarcoma diagnoses in 2019, and just over 5,000 deaths due to the disease.
Advances in sarcoma treatment are always evolving. For the latest research in sarcoma treatment during Sarcoma Awareness Month, we spoke to Judith K. Sato , M.D., director of the Musculoskeletal Tumor Program at City of Hope and professor and chair emeritus of the Department of Pediatrics.

What Makes Sarcoma Treatment Complex?

Sarcomas can be roughly classified into two major groups based on whether the tumor arises in bone or the soft tissues. These tumors can cause pain and swelling, with a mass at the site of origin. But according to Sato, these broad categorizations are only the beginning.
“There are over 250 different types of sarcomas,” Sato explained. “Unlike carcinomas, such as lung, breast or uterine cancer, which begin in the existing epithelial cells, sarcomas form in the immature mesenchymal cells. These are cells that can grow up to become bone, muscle, cartilage, blood vessels or nerves. When these types of cells become cancerous, they grow very rapidly.”

How Are Sarcomas Diagnosed?

Because of the number of types of sarcoma, and because they can occur in so many different places in the body, diagnosing them accurately can be complex. Pain is often the first sign that there is the possibility of a sarcoma, which is usually followed up with imaging tools like an X-ray or magnetic resonance imaging, but Sato stressed the importance of moving quickly for treatment at a cancer center.
“An X-ray will tell us a lot about the bone, including whether there’s a tumor or lesion, or many times even if it is benign or malignant,” Sato said. “But it’s important to come to a cancer center like City of Hope for a biopsy. This is because if the biopsy is performed incorrectly or using the wrong technique, patients run the risk of losing the limb due to contamination of the area being biopsied.”
The risk for receiving the wrong kind of biopsy is very real. Biopsies performed improperly may cause unnecessary damage to surrounding muscles or tissues, which can lead to major surgery and even possible amputation.

The Importance of Timely Care

Because sarcomas can grow so quickly, receiving timely care is critical. Unfortunately, patients often delay treatment while waiting for insurance company approvals, or may seek care from different facilities for different aspects of their treatment.
“At City of Hope, we’ve built a comprehensive program for patients with sarcoma,” Sato said. This means the patient doesn’t have to move from one hospital to the next in order to get the treatment they need. Rather than have a biopsy performed in one hospital, chemotherapy in another and physical therapy in a third facility, we can treat the whole patient here. This allows us to avoid the delays in the administration of treatment, which often result in a poor patient outcome.”

Advances in Pediatric OSTEOSarcoma

Sarcomas are treatable, either through surgery, chemotherapy, radiation or a combination of the three. But when bone sarcomas affect pediatric patients, there’s another concern: replacing lost bone with their growth plates in a patient who hasn’t finished growing. At City of Hope there is an option available: the expandable internal prosthesis.
“We have internal prosthetic devices that are controlled by special magnets that trigger expansion of the internal implant in a very controlled way, by a few millimeters at a time. The patient can even be awake and participate by pushing the button that controls the prosthesis,” Sato said. When this device is placed inside a still-growing patient, the internal prosthesis can grow and change as needed to match the growth of the child, allowing them full mobility and motor function.

Comprehensive Sarcoma Patient Database

Over the last two years, Sato has also been at work developing a web-based database of sarcoma patients and survivors, tracking over 500 data points including each patient’s diagnosis and outcome. In addition to the type and location of the tumor and treatment received, as well as any complications, this database also tracks details about the characteristics of the tumors themselves.
“The information we get from analysis of the resected tumor after treatment tells us so much, including how ‘dead’ the tumor is, how it responded to chemotherapy and how well this particular patient responded to specific treatment. It’s really one of the first examples of personalized medicine, because we’re looking at how the patient's own tumors respond to chemotherapy on an individual-patient basis.”
It is hoped that this database will allow Sato and her team to generate reports on the specifics of any kind of sarcoma across a network of patients across the West Coast, based on any common characteristic. For example, a soft tissue sarcoma located on the inside of the thigh may have a higher rate of complications due to radiation, as opposed to a sarcoma located on the outside of the thigh. With a few keystrokes, the team can review these details and better educate the patient about potential risks, concerns or complications.

The Potential of Isolated Limb Infusion

Doctors at City of Hope are also researching the efficacy of isolated limb infusion therapy for sarcoma patients. “We can infuse a drug into a vessel in an arm, for example, where there’s a mass that’s already been treated with chemotherapy and/or radiation, but which keeps coming back,” Sato explained. “What if you could infuse and hold that drug in a higher concentration, in that mass, in the arm?”
Doctors infuse the drug and apply a tourniquet, which keeps the drug in the area where the tumor is growing for a short period of time, from 45 to 90 minutes. Then the tourniquet is released and the drug exits through a vein catheter. This allows higher concentrations to be applied to the tumor without being released into the patient’s bloodstream. This is a treatment that requires an advanced level of precision and technique; patients with tumors that are most likely to respond to this type of infusion are selected, who have tumors in a location where use of a tourniquet is possible.
While challenging, it is important to remember that sarcomas are treatable and often curable. After treatment, patients can expect to be monitored closely for the first few years. After five years, recurrence rates go down significantly.

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