Considerations for Radiation Therapy in TSGCT



Shreyaskumar R. Patel, MD: Do you have any closing comments before we move on to the true multidisciplinary aspects of management and invoking systemic therapy?

Robert G. Maki, MD, PhD: I’m not sure if we’re going to mention it at all during the latter stages, but I’ll mention the role of radiation since we don’t have a radiation oncologist involved. In the old days, we didn’t have anything else, so people were injecting joints with P32 [phosphorus 32]. I’m not sure for what purpose, but it was at least something to do. Potentially, external beam radiation could be useful for some of these cases, at least in principle; but not being a radiation oncologist, I’m not sure what the outcomes are with that modality of treatment or the complications that can arise from that.

Shreyaskumar R. Patel, MD: I haven’t encountered a patient where we recommended radiation therapy. Some part of it may be, as we will discuss in the next segment, that we have some alternative options to utilize from a systemic therapy standpoint that we might be able to bring in. John made the comment about radiation, but again, Drs Abraham or Kim, have you had patients whom you have recommended radiation for? Are you following anybody who had radiation in the previous era? Are there any pearls or specifics you can share?

John A. Abraham, MD: I can say that we don’t use radiation nowadays for this disease. In the past—just as Dr Maki mentioned—both intraarticular and external beam type forms of radiation were used. I think it is clear based on studies that have patients who were treated with radiation that it does decrease the recurrence rate significantly, which we expect radiation to do, but the adverse effects from it are quite limiting around a joint.

In general, even for sarcomas, we are careful about radiating the joints because of long-term problems. We see significant arthrofibrosis from the joint, especially if you’re talking about the synovium, which is circumferential around the joint. When you start talking about using radiation circumferentially around the leg, you can see things like extensive lymphedema, even to the point of requiring amputation. You can see osteonecrosis of the bone from radiation therapy. The stiffness can be really severe. Whereas in another part of the body, the woody-type skin and loss of the oil glands may not make much of a difference; around a joint, when you get those skin changes, that alone can give you stiffness.

The big concern for radiation, which is always the case, is whether we are going to convert a benign tumor into a malignant tumor by treating it with radiation and then finding later that we have a radiation-induced sarcoma, or even converted a benign tumor into a malignant tumor. With the knowledge that there is a malignant form of TGCT [tenosynovial giant cell tumors], although extremely rare, it becomes an even greater concern. Am I doing a disservice by taking a benign tumor and converting it to a malignant tumor?

All those things together have made radiation fall out of favor for this disease even before the advent of medical therapies. With the advent of medical therapies, I feel radiation is something that probably has extremely limited indications. Maybe there are some indications where patients can’t have surgery, can’t have medical therapy, and have some severe problems with their joints, but it would be a patient on the extremely far end of a random bell curve who receives radiation these days.

Tae Won B. Kim, MD: I have not prescribed radiation to any of my patients for TGCT or PVNS [pigmented villonodular synovitis], for all the reasons that Dr Abraham mentioned. I just want to make a side note that when patients have come to us for an evaluation of recurrence and they had radiation therapy, in my mind a surgical option is further down the line. I don’t want to operate on those patients because with wound complications and further problems that start to lead down the path of potential amputation, you can’t control the disease surgically.

For those who are treating TGCT, but maybe not in large volumes or in the multidisciplinary-type setting, if you’re thinking about radiation, my advice would be to try to hold on radiation and send them to a place that has treated this before. If you use radiation, the surgical options start to narrow significantly.

Transcript Edited for Clarity

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