Hereditary and inflammatory bowel disease-related early onset colorectal cancer have unique characteristics and clinical course compared with sporadic disease

Abstract

Background: Early onset colorectal cancer (EoCRC), diagnosed in those <50 years old, is increasing in incidence. We sought to differentiate characteristics and outcomes of EoCRC in patients with sporadic disease or preexisting conditions. Methods: We evaluated 2,135 patients with EoCRC in a population-based cohort from the Canadian province of British Columbia. Patients were identified on the basis of presence of hereditary syndromes (n ¼ 146) or inflammatory bowel disease (IBD; n ¼ 87) and compared with patients with sporadic EoCRC (n ¼ 1,902). Results: Proportions of patients with preexisting conditions were highest in the youngest decile of 18–29 (34.3%, P < 0.0001). Patients with sporadic EoCRC were older, more likely female, and had increased BMI (P < 0.05). IBD-related EoCRC had the highest rates of metastatic disease, poor differentiation, adverse histology, lymphovascular, and perineural invasion (P < 0.05). Survival was lower in patients with IBD (HR, 1.80; 95% CI, 1.54–3.13; P < 0.0001) and higher in hereditary EoCRC (HR, 0.47; 95% CI, 0.45–0.73; P < 0.0001) compared with sporadic. Prognosis did not differ between ulcerative colitis or Crohn’s disease but was lower in those with undifferentiated-IBD (HR, 1.87; 95% CI, 1.01–4.05; P ¼ 0.049). Lynch syndrome EoCRC had improved survival over familial adenomatous polyposis (HR, 0.31; 95% CI, 0.054–0.57; P ¼ 0.0037) and other syndromes (HR, 0.43; 95% CI, 0.11–0.99; P ¼ 0.049). In multivariate analysis controlling for prognostic factors, hereditary EoCRC was unchanged from sporadic; however, IBD-related EoCRC had worse overall survival (HR, 2.21; 95% CI, 1.55–3.16; P < 0.0001). Conclusions: EoCRC is heterogenous and patients with preexisting conditions have different characteristics and outcomes compared with sporadic disease. Impact: Prognostic differences identified here for young patients with colorectal cancer and predisposing conditions may help facilitate treatment planning and patient counseling.