Risk factors for the development of desmoid tumors in patients with adenomatous polyposis syndrome

INTRODUCTION: in patients with adenomatous polyposis syndrome (APS), extracolonic manifestations are often detected. According to many researchers, desmoid tumors are the most common cause of death in patients with APS who underwent prophylactic bowel removal before polyps’ transformation into colorectal cancer. The inconsistent data in the current literature on the predisposive factors to the development of desmoid tumors in patients with APS prompted us to conduct our own research.

AIM: to evaluate the frequency of desmoid tumors in patients with adenomatous polyposis syndrome and to identify independent risk factors for the development of desmoid tumors.

PATIENTS AND METHODS: the single-center retrospective study included patients who underwent treatment for adenomatous polyposis syndrome and subsequent monitoring between January 2013 and January 2025. After the surgical stage of treatment, the patients were included in a long-term dynamic outpatient monitoring program. As part of this program, patients underwent annual endoscopic examinations of the upper and lower gastrointestinal tract, as well as CT scans of the chest, abdomen, and pelvis with intravenous contrast. The primary endpoint of the study was the detection of a desmoid tumor in a patient with APS. A univariate analysis followed by a logistic regression analysis was conducted to identify independent risk factors for the development of desmoid tumors in patients with APS.

RESULTS: In 79 (21.4%) out of the 369 patients included in the study desmoid tumors were detected on average, 18 (6 to 60) months after surgery for APS. In 90.1% of patients with a desmoid tumor, a pathogenic variant in the APC gene was detected. Based on the ROC analysis, it was found that the localization of pathogenic variant beyond codon 876 in the APC gene is more strongly associated with the development of desmoid tumor (AUC=0.60, p=0.01). As a result of the logistic regression analysis, it was revealed that the localization of the pathogenic variant in the APC gene beyond codon 876 (OR=2.15, 95% CI: 1.20-3.83, p=0.0097) and open access during surgery (OR=2.09, 95% CI: 1.18-3.71, p=0.0119) served as independent risk factors for the development of desmoid tumors in patients with APS.

CONCLUSION: the incidence of desmoid tumors detection in the studied cohort of patients with APS was 21.4%. The high risk of extraintestinal manifestations of APS confirms the need for long-term regular monitoring of patients after colorectal surgery, especially in the high-risk group – with the location of the pathogenic variant in the APC gene beyond codon 876 and/or after open surgery.

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