There are two main forms of TGCT: localized and diffuse. Both can grow in the bursae (fluid-filled sacs that cushion the bones, tendons, and muscles near your joints), the tendon sheaths (the membrane around a tendon), and the synovium (the membrane that lines your joints). In localized TGCT, the tumor affects a specific area of the joint and often occurs in the joints of the hands or feet, though it can appear in any joint in the body, according to the National Organization for Rare Disorders (NORD). Diffuse TGCT, in contrast, is much more spread out and affects the entire joint. It usually occurs in large joints, such as those in the knee, hip, elbow, shoulder, or ankle. TGCT is considered a “benign” condition, because it’s not cancerous and does not spread to other parts of the body, but that doesn’t mean it’s harmless. TGCT can cause chronic pain, stiffness, and impaired mobility and have a significant impact on quality of life. If untreated, TGCT — diffuse cases, in particular — can eventually lead to arthritic damage and deterioration of the joint, according to NORD. Treatment is crucial to stop the tumors from growing and further damaging the joint.
Treatment Options by TGCT Type
The main treatment for TGCT is surgery to remove the tumor. Factors such as the severity of your disease and whether your tumor is localized or diffuse will determine what type of surgery, medication, or other treatment options you and your doctor can consider. In cases of localized TGCT, the disease is in one discrete area of the joint and can typically be treated successfully with surgery, says Robert J. Wilson, MD, an assistant professor of orthopedic surgery at the Hospital of the University of Pennsylvania, in Philadelphia. “If you remove that nodule, the chances that it comes back or that you need further surgery in the area or other type of treatment is pretty unusual,” says Dr. Wilson. According to a review published in February 2017 in the journal Orthopaedics and Traumatology: Surgery and Research, 73 to 91 percent of patients with localized TGCT were found to have no recurrence of the disease 5 years after surgery. But, says Wilson, in cases where TGCT is misidentified as localized but is actually diffuse or the surgeon fails to remove all of the disease, the tumor may return. Diffuse TGCT is more challenging to treat, says Wilson. “Basically the entire lining of the joint is abnormal and involved by the tumor,” he notes. “That’s when you start to get into more extensive surgery and then treatment beyond surgery.” He compares synovectomy — the removal of the lining of the joint — to painting a room. “When you paint a room of a house, you may miss a spot or two,” says Wilson. “These joints have complex geometric shapes for which it’s very difficult to get every nook and cranny of the joint removed.” “One of the key take-home points about diffuse TGCT is that the severity of the disease can be different from one person to another,” says Wilson. He notes that some individuals may have diffuse disease that’s confined to the joint, while others may have disease that was in the joint long enough before diagnosis that it has grown and spread outside the joint. “That increases the risk that you may inadvertently leave some of the disease behind and it regrows,” says Wilson. Severe diffuse TGCT that’s widespread throughout the joint and difficult to remove completely may require multiple surgeries over several years to manage, according to Nicholas Bernthal, MD, chief of the division of musculoskeletal oncology at the David Geffen School of Medicine at UCLA. Fortunately, that is a small subset of diffuse TGCT, which itself is a subset of all TGCT cases. Dr. Bernthal estimates that only about 10 percent of TGCT cases are diffuse.
Surgery Options for Localized and Diffuse TGCT
The type of surgery used to remove the disease from a joint depends on factors such as the type of TGCT, the location of the affected joint, and the extent of the disease, according to NORD. Localized TGCT is typically treated with partial synovectomy, which involves removing only the nodular area of the lining that is diseased, says Wilson. Diffuse TGCT commonly requires a complete or total synovectomy, in which the entire lining of the joint is removed. Both partial and complete synovectomies can be done using open surgery or arthroscopic surgery. In some cases, the techniques may be used in combination.
Open synovectomy A surgeon makes an incision and opens up the tissue and the joint to see and feel the affected areas of the lining and remove the diseased areas.Arthroscopic synovectomy This involves a surgeon making small holes in the skin through which a camera can be inserted to reach down to the joint, such as the knee. “Depending on how extensive the surgery needs to be, you put an instrument into the knee that basically shaves the lining of the joint away,” says Wilson.
According to Wilson, arthroscopic synovectomy generally results in less of a scar and fewer complications, such as infections and wound problems, compared with open surgery, but he notes that one technique hasn’t been shown to be superior to the other in terms of how well they treat TGCT. The location of the tumor is one of the factors that can determine which technique a surgeon may choose. There are some joints, such as in the spine, that you can’t do a scope on easily, says Wilson. Then there are some scenarios in which using both techniques might work best, says Wilson. “That really is used mainly around the knee joint,” he says. “Some people have diffuse giant cell tumor that is so diffuse that it actually goes through the knee and goes outside the joint,” says Wilson. In the knee, that often occurs in the back of it, where major nerves and blood vessels to your foot and your leg are located, making the area difficult to operate on arthroscopically, explains Wilson. In such cases, a surgeon may remove the disease in the back of the knee with an open surgery and then use arthroscopic surgery for the disease that’s in the knee joint. Doctors may also decide what type of surgery or surgical technique to use based on an individual’s age, overall health, and other personal factors as well as the severity of their disease, says Wilson. “Sometimes we see patients with TGCT where it’s been there long enough that it’s inflamed the joint and caused enough pain over time that it’s degenerated the cartilage,” says Wilson. “Every once in a while, we see patients in their 50s and 60s where it’s the first time they showed up [with diffuse TGCT], and their joint has degenerated enough that we may go in and do a removal of the lining of the joint and also do a joint replacement surgery at the same time.” In these cases, notes Wilson, simply removing the lining of the joint is not enough to relieve pain and improve symptoms. And in very rare cases where the disease level is severe and repeated surgeries can’t improve pain and function, a doctor may suggest amputation. In general, amputation is considered if a person has severe “ankle or knee disease that has caused significant pain and dysfunction and has had multiple surgeries that have failed to eradicate the disease, as well as failed medicine and radiation treatment,” says Wilson. But he says that is becoming even more rare with improved treatment for TGCT.
Nonsurgical Treatment for TGCT
Doctors may also use radiation to treat TGCT. Radiation is used to help destroy any small bits of the tumor that are still there after surgery, says Wilson. “You can either use it before or after the surgery, but the goal is still the same whenever you use it, which is to decrease the risk that the tumor regrows in that area, thus reducing the risk that the patient will need additional surgery,” says Wilson. The radiation for TGCT, which is administered by a radiation oncologist, is generally a lower dose than that given for cancer, says Wilson. “The pros are that it helps lower the risk of needing additional surgery and is generally well tolerated,” says Wilson. “The cons are that it can cause stiffness and swelling of the treated area to a certain degree.” Wilson also notes that some people may be reluctant to undergo radiation because you’re using something typically used for cancer to treat a benign tumor. He points out that “very, very rarely, when you have radiation to an area, that can actually cause some of the normal tissue to down the road become a cancer.” He emphasizes that it’s extremely rare, but the risk is not zero. That’s why radiation therapy is something patients are counseled on extensively before they select it as part of their treatment, says Wilson. The main nonsurgical treatment for TGCT is medication, including some that have shown some benefit in treating diffuse TGCT but were originally designed to treat other diseases, such as imatinib and nilotinib, which are used to treat leukemia. Medications are used for people who have severe diffuse disease that can’t realistically be removed entirely with surgery without significant functional consequence, says Wilson. A typical scenario in which medication may be used to treat TGCT would be if a patient with severe diffuse disease of the knee has had multiple surgeries that failed to stop the disease or their pain and might be considering amputation. In August 2019 the Food and Drug Administration gave the go-ahead to a drug called pexidartinib, which became the first medication approved to treat diffuse, symptomatic TGCT that cannot be successfully treated by surgery. The main side effect is liver injury, which is why patients are followed closely with liver function tests, says Wilson. A medical oncologist may administer the medicine and do the monitoring. “We do not yet know if this medicine needs to be lifelong to prevent the disease from getting worse or if it is best used for a temporary period of time,” says Wilson. Along with surgery or other medical treatment — radiation, medication — physical therapy can play a role in helping you recover and regain mobility, says Wilson. While lifestyle and dietary changes won’t prevent someone from getting the disease or prevent it from coming back after treatment, he notes, physical therapy after surgery can help you regain strength of the muscles around the involved joint and prevent it from becoming stiff.
