Clinical Summary:

• Design/Population: This retrospective analysis of the French NETSARC+ database evaluated tumor characteristics, management patterns, and outcomes among patients with desmoid tumors treated between 2010 and 2024 across a national network of 26 reference sarcoma centers. 
• Key Outcomes: The proportion of patients undergoing surgery declined substantially over the study period, while larger tumor size and specific anatomical locations were independently associated with shorter progression-free survival (PFS). Median PFS was 47.7 months, and desmoid tumors were more frequently diagnosed in women. 
• Clinical Relevance: The findings demonstrate evolving management practices for desmoid tumors, including a marked reduction in surgical intervention, and reinforce the prognostic importance of tumor size and location when evaluating patients and developing individualized management strategies. 

Results from a large analysis of the French NETSARC+ database demonstrated a substantial decline in surgical management of desmoid tumors between 2010 and 2024, while identifying tumor size and anatomic location as prognostic factors for progression-free survival (PFS), highlighting evolving treatment practices and the importance of individualized risk assessment.

These findings were presented by Armelle Dufresne, MD, PhD, Centre Léon Bérard, Lyon, France, at the European Society for Medical Oncology (ESMO) Congress in Madrid, Spain.

In this study, researchers evaluated data from 3457 patients with desmoid tumors enrolled in the NETSARC+ database between 2010 and 2024, a national network of 26 reference sarcoma centers funded by the French National Cancer Institute. 

The analysis assessed tumor characteristics, management strategies, and clinical outcomes, including changes in surgical treatment patterns and factors associated with progression-free survival (PFS). 

The reported incidence of desmoid tumors was 3.02 cases per million individuals annually. Women accounted for 70% of cases, with a median age at diagnosis of 40 years. Women were diagnosed at a younger age than men (38 years vs 49 years; P < .001). 

Median tumor size at diagnosis was 55 mm, with larger tumors observed among men than women (70 mm vs 50 mm; P < .001). The most common tumor location was the trunk wall (51%), followed by intra-abdominal sites (15%), upper limbs (8%), lower limbs (7.5%), gastrointestinal sites (6%), and head and neck (4%). Other locations accounted for 8% of cases. 

Tumor distribution differed by sex. Trunk wall tumors were more frequent among women than men (58% vs 36%), whereas internal tumors (25% vs 11%) and gastrointestinal tumors (11.7% vs 3.7%) were more frequent among men.

Desmoid tumors occurred in the context of Gardner syndrome in 2.5% of patients. Additionally, 12% of patients had a personal history of cancer, and 51 patients had previously received radiotherapy. Diagnosis occurred during pregnancy in 104 patients, with 58% of these tumors located in the abdominal wall.

Overall, 35% of patients underwent surgical treatment during the study period. However, the proportion undergoing surgery declined substantially over time, from 47.2% between 2010 and 2014 to 32% between 2015 and 2019 and 22.1% between 2020 to 2024. 

Men underwent surgery more frequently than women (36% vs 30%; P < .001). Surgical intervention also varied according to tumor location. Surgery rates were highest among patients with gastrointestinal tumors (78.5%) and internal tumors (46%).

Among patients with available surgical margin data (n = 799), complete resection with negative margins was achieved in 47% of patients, microscopically positive margins were reported in 39% of patients, and macroscopically positive margins were reported in 14% of patients. 

Median PFS was 47.7 months. In multivariable analysis, larger tumor size was associated with shorter PFS (hazard ratio [HR], 1.003; P < .001). 

Tumor location was also independently associated with PFS. Head and neck tumors demonstrated the highest strongest association with shorter PFS (HR, 2.43; P < 0.001), followed by lower limb tumors (HR, 1.324; P = .027), upper limb tumors (HR, 1.299; P = .017), and trunk wall tumors (HR, 1.287; P = .006).

These findings reinforce the prognostic importance of anatomical location and tumor size in patients with desmoid tumors, while demonstrating a substantial shift away from surgical intervention over the study period.

The investigators concluded that the rarity and heterogeneous clinical presentation of desmoid tumors underscore the importance of large-scale registry analyses to inform clinical research and treatment strategies. 

The decline in surgery rates reflects evolving management recommendations, while the findings confirm the prognostic relevance of tumor location and highlight the need for further investigation into the potential mechanical and hormonal influences associated with pregnancy-related desmoid tumors. 

Source:

Dufresne A, et al. Desmoid tumors (DTs) from the NETSARC+ registry: Tumor characteristics, management strategies, and outcomes in 3457 patients. Presented at ESMO Congress. October 23–27, 2026; Madrid, Spain. Abstract 3723RO.