Balancing Symptoms and Current Therapies in Desmoid Tumor Management

Nam Quoc Bui, MD

Clinical Associate Professor of Medicine

Stanford Cancer Institute

Stanford, CA

Targeted Oncology: What does the Desmoid Tumor Working Group recommend for patients with potential desmoid tumors?¹

Nam Quoc Bui, MD: The treatment algorithm [recommends] diagnosis by core needle biopsy, get pathology, if needed send out to a sarcoma center that has pathology to look at it—because they aren't very common, you need to make sure you're getting the diagnosis right—and next-generation sequencing if needed. The first-line approach is active surveillance for 1 to 2 years.

I think this is a reasonable approach for patients with asymptomatic or minimally symptomatic desmoids or something that, if it grows, it's not going to cause immediate end organ dysfunction or complication. I think there is probably a role for upfront treatment in cases of patients who are symptomatic or have some tumor that, if it grows, will cause some sort of problem. In case of progression, it depends on the different locations.

How does the location affect the treatment of the desmoid tumor?

For abdominal wall [desmoid tumors], they suggest surgery…. We've had pretty good local control rates with cryoablation. We don't do surgery because patients end up needing some abdominal wall reconstruction, sometimes mesh, or sometimes we need to reconstruct the inguinal canal and [patients could] have hernias and issues like that. We honestly don't do that many surgeries unless the patient requests it. Sometimes patients are very firm on [wanting it removed]. We tend to either do medical treatment, surveillance, or ablation-type procedures. We do a lot of cryoablation at Stanford, and we're going to publish [about] it some point.

We also have intraabdominal and retroperitoneal [tumors]. Those tumors can get a bit tricky, because patients can get symptoms related to bowel obstructions or ureter obstructions. There's lots of stuff in the abdomen that can get obstructed with these desmoid tumors. I have patients who have chronic small bowel obstruction from their desmoids, and they have to be on total parenteral nutrition. It's very difficult to manage. Even though they're not that big, they can be in bad locations.

Extremity tumors tend to be a little bit easier because there are not as many organs around there that run into problems with mass effect. You have a lot more leeway to do ablation procedures, sometimes surgery if you want, or medical treatment or just observation. For head and neck, [it] has a lot less real estate than the extremities, so sometimes you can run into problems with it running into the brachial plexus or starting to get into the airway or throat, although not that commonly. I think it varies depending on the patient.

I definitely have had patients who had undergone surgery, then the tumor comes back pretty frequently or pretty rapidly, and then you are stuck in the same problem, but now, if they have undergone surgery, they potentially have complications from the surgery. I think we've moved from the surgical frontline approach to more of an active surveillance type approach for desmoid tumors.

What do the NCCN guidelines suggest for this patient population?²

The NCCN clinical practice guidelines for desmoid tumors talk about making sure that you screen for colorectal cancer or familial adenomatous polyposis [FAP], knowing that about 10% to 15%, especially for intraabdominal ones or young patients, will have it. Having FAP has an effect on long-term mortality if you do not diagnose and treat it, because these patients can get colon cancer at a very early age. Make sure that you are screening them for that.

The most recent version [of NCCN for desmoid tumors is from] 2024. Anatomic location where progression would not be morbid—so if it grows, it's not going to cause an immediate problem—we recommend observation with imaging with either CT or MRI, and if it's stable or regressed, you continue observation. If it's progression, then you go on to either continue ongoing observation, because we've seen in trials, even patients that have grown by 10% or even 20%, a high number of them will regress.... Then, if it's an anatomic location where regression would be morbid, for documented regression, you go on to systemic therapies or local therapies. If there's no documented progression, then you consider a short course of observation with a CT scan, or you can treat them if there's concerns for morbidity or significant symptoms of the patient. Active surveillance is our default but we take into account morbidity if the tumor grows or [leads to] symptoms where patients are on a ton of pain medication and need symptomatic care.

How does treatment change based on anatomic location for active disease according to the NCCN?

For patients who need active therapy for progressive, morbid, or symptomatic disease, if it's intraabdominal or retroperitoneal, options include systemic therapy and surgery if resectable. Options for all other sites include...systemic therapy, ablation/embolization…definitive radiation—that has been used before in desmoid tumors, and we use it for select patients. Because this patient population tends to be younger, we try to avoid giving radiation to young patients, because you can end up having secondary malignancies or radiation fibrosis, and you don't want to turn a non-malignant condition into a malignant cancer that can kill somebody—then surgery if it is resectable. Then, if you have surgery, then you can adjust whether you give adjuvant radiation. We don't give adjuvant radiation, so I'm not sure where these [recommendations] are coming from. We try to avoid surgery, if possible, but some patients do end up getting surgery if deemed in a multidisciplinary discussion that it would be beneficial for the patient.

_References:

_{1. Desmoid Tumor Working Group. The management of desmoid tumours: A joint global consensus-based guideline approach for adult and paediatric patients. Eur J Cancer. 2020;127:96-107. doi:10.1016/j.ejca.2019.11.013}

_{2. NCCN. Clinical Practice Guidelines. Soft tissue sarcoma, version 4.2024. https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1464}