Familial adenomatous polyposis Towards personalized care

Patients with familial adenomatous polyposis (FAP) develop hundreds to thousands of colorectal adenomas and have a 100% risk of developing colorectal cancer, if left untreated. Patients undergo (procto)colectomy and lifelong endoscopic surveillance to prevent cancer.
Current guidelines on polyposis do provide general recommendations on endoscopic surveillance. In chapter 3, we present a recently developed personalized endoscopic surveillance and intervention protocol.
Even after proctocolectomy, patients are at risk of developing adenomas in ileal mucosa. In chapter 4 we showed that patients with ileal pouch-anal anastomosis are at higher risk of developing ileal adenomas than patients with end ileostomy. Most patients with FAP also develop duodenal adenomas and are at risk of duodenal cancer. In chapter 5 we demonstrated the safety of cold snare polypectomy for superficial duodenal adenomas, whereas no bleedings or perforations occurred. Some patients with extensive duodenal polyposis require surgical resection. In chapter 6 we described the outcomes of pancreas-preserving total duodenectomy, which appeared to have substantial morbidity but preserved pancreatic functions in most patients. After duodenectomy, patients stay at risk of developing jejunal and gastric adenomas and cancer (chapter 6 and 7) and therefore endoscopic surveillance is still required. A subset of patients with FAP develop desmoid tumours, usually shortly after colectomy. Although our meta-analyses showed no difference (chapter 8), chapter 9 shows that patients are at increased risk of desmoid after an open proctocolectomy with ileal pouch-anal anastomosis. In chapter 10, we describe a large family with MSH3-related adenomatous polyposis, a recently recognized predisposing gene for adenomatous polyposis.