William D. Tap, MD: Hello, and thank you for joining this OncLive® Peer Exchange® entitled “Systemic Management of Advanced Soft Tissue Sarcoma.” Soft tissue sarcoma is a complex and heterogeneous disease that is often misdiagnosed and difficult to treat. Moreover, until recently, systemic therapies that improve overall survival in patients with unresectable disease were virtually nonexistent. In this OncLive® Peer Exchange®, I am joined by a panel of experts in sarcoma research. Together we will look at the most recent information surrounding treatment of soft tissue sarcoma and the use of modern therapies in the setting of advanced disease. We’ll provide personal perspective on how to apply the latest data to clinical care.
I am Dr. William Tap, medical oncologist and chief of the Sarcoma Medical Oncology Service at Memorial Sloan Kettering Cancer Center in New York, New York. Participating today on our distinguished panel are Dr. Kristen Ganjoo, associate professor of medicine and director of the Sarcoma Program at Stanford University Medical Center in Stanford, California; Dr. Richard Riedel, associate professor of medicine in the Department of Medicine and member of the Duke Cancer Institute at Duke University School of Medicine in Durham, North Carolina; Dr. Jonathan Trent, sarcoma medical oncologist and associate director for clinical research at the Sylvester Comprehensive Cancer Center, a part of the University of Miami Health System, in Miami, Florida; and Dr. Victor Villalobos, assistant professor of medicine, director of Sarcoma Medical Oncology, and director of Molecular Oncology Therapeutics at the University of Colorado, Denver. Thank you so much for joining, and let’s begin.
Dr. Trent, John, do you want to talk to us a little bit about sarcoma to get us started?
Jonathan C. Trent, MD, PhD: Yes, Bill, that’s a great idea. Sarcoma is a collection of different cancers. In fact, if one were to look in the pathology textbooks, there are over 200 different types of soft tissue sarcomas. Each one of those is a different type of cancer. They’re fundamentally different in the way that they present, fundamentally different in their metastatic pattern, and fundamentally different in their biology, as well as treatment, that we’re going to hear about today.
William D. Tap, MD: You can imagine that with such a diverse disease, there are a lot of dilemmas, not only that we face at academic centers but also in the community. What are some of the diagnostic dilemmas? How do we approach these 80 to a few hundred different types of diseases, Kristen?
Kristen N. Ganjoo, MD: One of the most important things is the pathology. We have to have an expert pathologist who is experienced in sarcomas. As Dr. Trent was saying, with 200 different kinds of sarcomas that are so rare, we need to have an expert pathologist subtype the sarcoma. Each subtype is treated differently, so we need to have the correct diagnosis. The other issue is late diagnosis. That’s one of the reasons. If you don’t have an expert pathologist, the diagnosis is sometimes different than what we actually have.
William D. Tap, MD: Bumps and lumps are common. Sarcomas are rare. How do you work up patients, Victor, when you first see them? What are some of your initial thoughts?
Victor M. Villalobos, MD, PhD: Diagnoses of these tumors are quite difficult because benign tumors are 100-fold more common than malignant ones. I can’t tell you how often we have patients who had a tumor that was growing and then they had an “oops” surgery where we’re now trying to clean up the problems that were left behind. I think a good rule of thumb is if it’s bigger than a golf ball or it’s hurting or it’s growing, don’t touch it. Send them to an experienced orthopedic oncologist or surgical oncologist who knows that they’re doing with sarcomas. I think that really can mitigate a lot of problems down the road.
William D. Tap, MD: I agree. It’s the initial treatment and planning that’s going to be really important. What are some of the tests that you would use for these patients, Rich?
Richard F. Riedel, MD: I think that once you have a confirmed diagnosis—and, as Kristen mentioned, the pathology is extremely important—you want to understand what the extent of the disease is, and that would involve staging the patient. Obviously, you want to have good imaging done and not only for the primary site, which, for a sarcoma that occurs in the extremities, is typically an MRI. For a sarcoma that occurs in the trunk region, it’s oftentimes a CT scan. CT imaging, contrasted imaging, is enough, and then you want to image the chest as the lungs are the most common site of distant spread. The role of a PET scan can be debated, but I think at a minimum—for an extremity sarcoma in particular—order an MRI or CT scan of the chest.
William D. Tap, MD: What about things like next-generation sequencing? That’s very common in cancer. With so many different diseases, does it help us? Does it hurt us? What do we use that for?
Jonathan C. Trent, MD, PhD: I think that’s a really good question, and it goes back to all the different types of sarcomas. Remember, each one of these is a different type of cancer. In some types—for instance, gastrointestinal stromal tumors—using next-generation sequencing to understand the driver mutation not only helps make the diagnosis but helps us subsequently understand the natural history and select appropriate treatment for patients.
William D. Tap, MD: Any thoughts? Is that something that you routinely do or routinely recommend for patients?
Kristen N. Ganjoo, MD: I’ve actually been using next-generation sequencing for about 80% of my high-grade sarcomas—not the low grades, but the high grades—and I have been successful in certain cases to actually change the diagnosis.
William D. Tap, MD: That’s an important concept. I think most of us, if we see patients coming from outside of a tertiary care center, often change the diagnosis maybe 15% of the time, sometimes higher. To us, that has meaning because there could be very specific treatments for certain subtypes.
Tanscript Edited for Clarity