Understanding Desmoid Tumor Rates, Diagnosis, and Concerns

Desmoid tumors, rare, locally aggressive soft tissue neoplasms, can occur in any anatomic location. In a virtual Case-Based Roundtable with participants from the Great Lakes and Great Plains regions, Steven I. Robinson, MBBS, an associate professor of oncology and medical oncologist at the Mayo Clinic in Rochester, Minnesota, detailed the epidemiology, common mutations, and the high recurrence rates associated with these tumors. Robinson also reviewed the potential for spontaneous regression and progression of an abdominal wall desmoid tumor.

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Targeted Oncology: Could you discuss the characteristics and prevalence of desmoid tumors?

Steven I. Robinson, MBBS: Desmoid tumors are rare; they'll account for 3 to 5 cases per million people.¹ When we think of somewhere between 13,000 to 15,000 soft tissue sarcomas diagnosed every year in the United States, and if desmoid tumors are 10% or less, then we'll expect somewhere between 1000 to just over 1500 cases per year. They tend to be in younger patients from age 20 to 44 with a slight female predominance. Most patients will have sporadic desmoid tumors, but about 10% to 15% will have the APC gene mutation that's characteristic and drives familial adenomatous polyposis [FAP].²

These are locally aggressive, proliferative fibromatoses, hence the name aggressive fibromatoses, and we think that the cell of origin is a myofibroblast or the mesenchymal fibroblast. Desmoid tumors can occur in any anatomic location. They may be multifocal, especially in patients with the APC gene mutation or FAP, but more importantly, these are associated with a very high risk of recurrence following resection, anywhere from 24% to nearly 80% depending on the series and literature, and this is irrespective of the tumor margins…. These are growths that can be in problematic areas. Patients can present with pain; they can present with obstructive symptoms, and if it's in the abdomen, it can limit their function and their mobility. It's those neighboring structures, and depending on which neighboring structure is nearby, will result in the symptom that the patient experiences.

What historical data have shown us more about desmoid tumors?

Over time we have learned a lot, and we know that desmoid tumors can spontaneously regress, they can be stable, and 40% can progress at presentation. In fact, a lot of the early work done in some retrospective single-institution series from 2007, 2009, 2011, and on led to 3 prospective cohort studies, where the French Sarcoma Group, the Italian Sarcoma Group and the Dutch Sarcoma Group have since published between 2020 and 2023, their experience with, collectively, over 100 patients with desmoid tumors; 300 each cohort, 100 in the French, 105 in the Dutch, and 108 patients in the Italian cohorts. This is emphasizing the point that patients can regress if they are actively surveyed in the initial portion of the care, or if patients initially progress and you follow them, we can even see spontaneous regression.³

Where is it most common for patients to have desmoid tumors?

It can occur in any anatomic location.⁴ About one-fifth will be intra-abdominal, and if we see the intra-abdominal desmoid tumors, it should cue us in to see if they have FAP. They can be in the upper and lower extremities at fairly equal rates. We can see them on the chest wall, the head and neck region, and the abdominal wall. When it's in the abdominal wall location, this is the site that is most likely to spontaneously regress.

For the symptoms that patients can experience depending on the location, for most of these it will be that impact of pain or discomfort or a palpable lump. But when its intra-abdominal, there's the risk of mechanical obstruction. People have looked at some of the risk factors associated with desmoid tumors. I mentioned a slight female predominance, and we do see an uptick when patients have had a recent pregnancy or a hyper-estrogenic state, but when patients have trauma such as surgery or recent injury, we can see desmoid tumors appear. For example, I [discussed] this high risk of recurrence, even with surgical resection—I've had more than 1 patient where the desmoid tumor was operated on and then they saw me with a multifocal recurrence around the resection cavity.

What kind of mutations are usually seen with desmoid tumors?

The vast majority of desmoid tumors will be sporadic in nature, 85% to 90%, and there'll be mutations in the CTNNB1 gene, and about 10% to 15% will have the APC gene.⁵ These are mutually exclusive; if you have somebody with the APC gene, they're not going to have the CTNNB1 mutation.

If you have either a mutation the APC gene or CTNNB1 gene, it will disrupt CTNNB1 degradation and lead to nuclear translocation and ultimate target gene transcription and development of the desmoid tumor.

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DISCLOSURES: There are no relevant disclosures.

REFERENCES:

1. Bektas M, Bell T, Khan S, et al. Desmoid Tumors: A Comprehensive Review. Adv Ther. 2023;40(9):3697-3722. doi:10.1007/s12325-023-02592-0

2. Penel N, Chibon F, Salas S. Adult desmoid tumors: biology, management and ongoing trials. Curr Opin Oncol. 2017;29(4):268-274. doi:10.1097/CCO.0000000000000374

3. Lee YS, Joo MW, Shin SH, Hong S, Chung YG. Current Treatment Concepts for Extra-Abdominal Desmoid-Type Fibromatosis: A Narrative Review. Cancers (Basel). 2024;16(2):273. Published 2024 Jan 8. doi:10.3390/cancers16020273

4. Peng PD, Hyder O, Mavros MN, et al. Management and recurrence patterns of desmoids tumors: a multi-institutional analysis of 211 patients. Ann Surg Oncol. 2012;19(13):4036-4042. doi:10.1245/s10434-012-2634-6

5. Kasper B, Baumgarten C, Garcia J, et al. An update on the management of sporadic desmoid-type fibromatosis: a European Consensus Initiative between Sarcoma PAtients EuroNet (SPAEN) and European Organization for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG). Ann Oncol. 2017;28(10):2399-2408. doi:10.1093/annonc/mdx323