# Management of desmoid tumors associated with familial adenomatous polyposis: a three-decade experience of a tertiary center in Brazil

## TL;DR

This study examines desmoid tumors in patients with familial adenomatous polyposis, finding a high prevalence and significant complications.

## Contribution

The study provides a three-decade retrospective analysis of desmoid tumor prevalence and management in FAP patients in Brazil.

## Key findings

- 17.7% of FAP patients developed desmoid tumors during follow-up.
- Patients with a family history of the tumor were more likely to develop DTs.
- High morbidity and mortality rates were observed despite surgical treatment.

## Abstract

Aggressive fibromatosis, also known as desmoid tumor (DT), is a locally aggressive myofibroblastic neoplasm originating from deep soft tissues, characterized by an infiltrative growth pattern with a tendency for local recurrence. DTs account for 0.03% of all neoplasms, and cases associated with familial adenomatous polyposis (FAP) account for 5–15% of DTs.

The aim of this study was to report the prevalence of DTs in patients operated on for FAP, describe the epidemiological profile, and evaluate the risk factors for tumor development, treatments performed, associated complications, and follow-up.

This retrospective study assessed the medical records of patients with FAP who underwent surgery between 1990 and 2021 and developed DTs during follow-up.

In the study period, 147 patients with FAP were operated on; of these, 97 underwent total proctocolectomy with ileal-pouch anal anastomosis, 33 underwent total colectomy with ileorectal anastomosis (IRA), 14 underwent total proctocolectomy with terminal ileostomy, and three underwent total colectomy with partial proctectomy and low IRA using an ileal-pouch. A total of 26 patients (17.7%) developed DT; most were female (61.5%), were White (73.1%), and had a family history (84.6%). The most frequent complications were intestinal and ureteral obstructions. Long-term follow-up showed that six patients were free of disease, 14 were stable and undergoing drug therapy, four died due to complications of the disease, and two were lost to follow-up.

The prevalence of DT tumor was relatively high and more commonly observed in patients with a family history of the tumor. The disease presented high rates of morbidity and mortality.

Desmoid tumor (DT) is an aggressive myofibroblastic neoplasm characterized by an infiltrative growth pattern with a tendency for local recurrence without metastatic potential.

The clinical symptoms of DTs depend on their location, size, number of lesions, and growth pattern. DTs can be classified into intra-abdominal, abdominal wall, and extra-abdominal.

FAP cases associated with DTs account for 5–15% of this type of tumor. They often have a more aggressive course and may present as more extensive, multifocal tumors, occurring up to 10 years earlier than sporadic ones.

The treatment of DTs is multimodal and depends on several factors, such as tumor size and location, symptoms, and lesion growth pattern. They include surgery, active monitoring, radiotherapy, chemotherapy, hormone therapy, nonsteroidal anti-inflammatory drugs, and ablation techniques.

Aggressive fibromatosis, also known as desmoid tumor (DT), is a locally aggressive myofibroblastic neoplasm originating from deep soft tissues, characterized by an infiltrative growth pattern with a tendency for local recurrence without metastatic potential. DTs account for 0.03% of all neoplasms and <3% of soft tissue tumors in the general population. The incidence of DTs in European countries is 2–5 cases per one million inhabitants, with a mean age at diagnosis of 35 years. Cases associated with familial adenomatous polyposis (FAP) syndrome account for 5–15% of DTs.

In this study, the prevalence of desmoid tumors (DTs) in patients operated on for familial adenomatous polyposis (FAP) was relatively high (17.7%) and comparable with that reported in the literature. DTs were more commonly observed in patients with a family history of the condition. Surgical treatment was the most prevalent, and morbidity and mortality rates were high. However, many questions remain regarding the optimal management of DTs. Although rare, the disease is characterized by a low prevalence but a high rate of complications, and currently, there are no standardized treatment protocols. Further studies are needed to obtain a better follow-up of these patients to enable increased survival through earlier diagnosis, more effective treatment strategies, and, where possible, prevention.