The epidemiology of desmoid tumors in Denmark

1

Introduction

Desmoid tumors (DTs), or aggressive fibromatosis, are rare, clonal soft tissue neoplasms characterized by locally aggressive fibroblastic proliferation, significant morbidity, and no metastatic potential [1] . The estimated annual incidence of DTs in the general population is 2–5 cases per million 234 . Individuals between the ages of 15 and 60 are most commonly affected [56] .

The etiology of DTs is multifactorial. Most DTs (85–90%) arise sporadically. DTs also develop in about 10–25% of patients with familiar adenomatous polyposis (FAP) 6789 . One case series suggests up to thirty percent of DT patients have a history of trauma at the anatomical site where the DT arises [10] , including surgery such as Caesarean section. High estrogenic states, pregnancy, and female sex have been reported as risk factors, leading to a two-to-three times higher prevalence of DTs in females [1011] . Common anatomic DT sites include the abdominal wall, limbs, girdles, and the mesenteric area. FAP patients frequently experience intra-abdominal DTs [12] .

According to the 2018 European Society of Medical Oncology (ESMO) and the 2020 US National Comprehensive Cancer Network (NCCN) guidelines for soft tissue and visceral sarcomas [1314] , treatments may include surgery, isolated limb perfusion, cryoablation, radiotherapy, or systemic medical therapies, including chemotherapeutic agents, tyrosine kinase inhibitors (TKIs), non-steroidal anti-inflammatory drugs (NSAIDs), and hormonal therapies like tamoxifen [1315] for progressing cases.

Historically, total resection has been the mainstay DT treatment, but post-surgical recurrence rates are between 22% and 76% [16] . These procedures may be highly morbid, causing potential disfigurement and functional impairment. By contrast, an initial active surveillance approach of monitoring the DT radiographically prior to committing to resection did not negatively impact outcomes but lowered overall morbidity in stable, asymptomatic cases [17] . The first regional (European) [18] recommendations and global consensus guidelines [19] to advise initial active surveillance among certain patients were released in 2014 and 2020, respectively. Interest in avoiding debilitating surgical interventions is increasing.

Due to the rarity and complex clinical heterogeneity of DTs, high-quality evidence regarding their etiology, treatment, and prognosis is limited. Herein, we describe the epidemiology, demographic, clinical, survival, and healthcare resource utilization (HRU) characteristics of DT patients compared to a matched comparison cohort from the general population.