Explaining TGCT, the Rare Tumor Causing Pain and Limited Joint Mobility

There are not many patients with tenosynovial giant cell tumors, or TGCTs, with one expert telling CURE® that “about one in 1 million patients” will be affected by the condition.

The condition can cause inflammation, pain and limited joint mobility. As part of the “Speaking Out” series, Dr. Gina D’Amato, a professor of medicine at the Sylvester Comprehensive Cancer Center, explained the cause of TGCT and how it can impact patients’ lives.

“There's a difference between benign and malignant — benign means that it does not have the ability to spread to other organs and be life-threatening, where malignant can spread to other organs and be more life-threatening — so, it's a benign tumor that is a rare tumor, it's in the subtype of connective tissue tumors,” D’Amato said. “It starts out in the connective tissue around the joints, so it starts out from synovial fluid. And there's a specific gene mutation that occurs and what happens is, there's a cluster of abnormal cells that then bring inflammatory cells to the tumor, and then it causes a lot of inflammation, pain and joint dysfunction, a lack of range of motion.

“So, [it] usually occurs in patients between the ages of 20 and 40, [with a] slight predominance [among] females, but it can affect men as well. And the most common joint is the knee, but it can affect other joints, like the hips or the hands or the feet. So, it's rare, about one in 1 million patients will get it. … The cure of the of the tumor is surgery, but unfortunately, oftentimes it will recur and then affect quality of life of patients.”

During the conversation, D’Amato also discussed advancements in TGCT awareness and treatment over the past two decades, but noted that the relative rarity may result in a lack of awareness for both patients and providers, leading to misdiagnoses or delayed diagnoses, while

disparities in access to and affordability of healthcare can also lead to patient disadvantages.

Among recent advancements noted by D’Amato were the findings of the phase 3 MOTION trial, presented earlier this year at the American Society of Clinical Oncology (ASCO) annual meeting, evaluating the drug vimseltinib among patients with TGCT.

“Patients were randomized to receive in vimseltinib versus placebo, and it showed that the treatment improved pain, quality of life, range of motion function,” D’Amato said. “So it's a very effective drug and it was well-tolerated. So, it’s likely that drug will become FDA approve within the year, I would say within a year.”

This program was made possible with support from Deciphera. For more information on tenosynovial giant cell tumors (TGCTs), click here: https://www.tgcttruth.com/

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