Monitoring Desmoid Tumor Progression with Strategic Imaging Intervals

Desmoid tumors pose unique management challenges due to their propensity for recurrence. Tony Philip, MD, director of Quality and Patient Safety for Medical Oncology at Monter Cancer Center and assistant professor at Hofstra/Northwell, moderated a virtual Case-Based Roundtable discussion with participants from New Jersey, New York, and Pennsylvania. Philip emphasized that tumor location and molecular markers influence monitoring and treatment decisions. Participants discussed individualized imaging intervals and unnecessary surgery or radiation because of the disease’s high recurrence risks and potential for malignant transformation.

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This article is part 2 of a 2-part series from a Case-Based Roundtable event.

DISCUSSION QUESTION

What concerns do you have for patients with desmoid tumors?

Madhuri Yalamanchili, MD: Are there any characteristics that would give you a clue as to prognosticators, clinical or pathologic, that a patient would experience progression?

Tony Philip, MD: I think of it from a location standpoint first. Let's say someone had a desmoid tumor in their head and neck area. That would make me more nervous in terms of growing and affecting a critical structure in that sense, as opposed to maybe a desmoid that's in the thigh that they're not having much in terms of symptoms from. That would make me less concerned. Abdominal or things that are involving the mesentery makes me nervous, because they can end up having bowel or abdominal pain issues. That sometimes biases me to scan them a little bit sooner if they're not symptomatic yet. I find they all kind of declare themselves quicker. From a molecular standpoint, if they had APC mutations, they tend to be multifocal, maybe not treating them earlier, but enough to watch them a little bit closer, especially if they're asymptomatic. That's the way I've thought it through in my mind.

DISCUSSION QUESTIONS

How frequently should imaging (e.g., MRI) be performed to monitor desmoid tumor progression during active surveillance?

Philip: What would you consider in terms of your imaging modality?

Sandeep Malik, MD: I'm not an expert, but these are slow growing tumors. It's hard to say which choice is good. Even if I have someone with palpable lumps sitting in front of me, I may not need a scan to demonstrate what's happening to it, because if this is something where I may not be able to monitor it clinically. I may end up getting it every 6 months to begin with, and if I don't find any velocity in growth, I may switch to annually.

Philip: That's a very reasonable approach. I think for someone who has something in an area where you can appreciate and follow, whether it's in the leg or shoulder or something like that, maybe you don't image them as closely as someone who has something intra-abdominal. So I think location matters there. I think about spacing it out as people go on in their treatment if they have disease stability, maybe a little bit tighter together in the beginning, every 4 to 6 months, depending on what's going on, but quickly try to go to every 6 months or a year if they look fairly stable after the first year or 2.

Dr Thomas, what do you think about in terms of imaging these patients?

Lisa Thomas, MD: I like [imaging] every 6 months. I do think they're slow growing. The patient who I have on tamoxifen had a very slow growing tumor, but the patient who needed cryotherapy was slow growing, and then all of a sudden, the tumor took off. I wish I had rebiopsied it before I did the cryotherapy, because you wonder if it is transforming to something more aggressive.

Philip: About the transforming part...knowing that these patients are young, this is technically something that's benign, so I would try to avoid radiating them whenever possible, because that's when you're going to run more of the risk of transforming it into something more aggressive and malignant. As far as I recall, the rates for a standard desmoid that's never been treated and morphing into something else, a more aggressive sarcoma, I think is on the more unlikely side, unless it's been radiated and now it's morphing into something like a radiation-induced sarcoma, potentially. Try to avoid radiation whenever possible, and frankly, I think even surgery whenever possible for these patients is key.

Thomas: Has the paradigm about surgery changed? Because I feel like the patient who I have on tamoxifen, I've probably been taking care of her for 10 years. She hasn't had any surgery in the interim. But before that, they were operating on her at least once a year for a few years. So it seems like they thought they could remove these, but then they figured out they can't—not even remove them, that they could eradicate them surgically. I think the paradigm has changed though, leave them alone.

Philip: That's what I'm trying to instill in more and more of our local surgeons. Because I think to them, depending on where they trained and when they trained, they see it in front of them, it's "benign," and they think they can just get it out. But I find inevitably, they come back, and the tumor has positive margins, or it recurs. I may end up meeting some of these patients after their second or third recurrence, and it keeps coming back, [and they don't want surgery] anymore. I tell them to let us try and do something different. I think it takes a lot of education of the surgeons themselves to know not to send them for repeated abdominal surgeries or trying to get "positive margins."

Arunabh Sekhri, MD: Do you see mostly local recurrence? You don't really see metastasis with this?

Philip: Yes, so I would say from a non-germline patient—let's say they have no evidence of APC, it's a sporadic desmoid tumor—we should not see "metastatic disease" of that desmoid. As opposed to that patient who has an abdominal desmoid who may have germline APC, they may have multifocal sites of their desmoid tumor. That's the way I see it. But if someone has a sporadic desmoid tumor in their leg, I do not expect it to pop up somewhere else for the most part.

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DISCLOSURES: Philip previously reported honoraria from SpringWorks Therapeutics and a consulting or advisory role with Foundation Medicine, Daiichi Sankyo/AstraZeneca, and Deciphera.