Clinicopathological features and cancer-specific survival in young patients with ulcerative colitis-associated colorectal neoplasia: a nationwide cohort study in Japan.

Abstract

Background: The incidence of ulcerative colitis-associated colorectal neoplasia (UCAN) is increasing, but clinicopathological features and outcomes in young patients remain unclear. We aimed to clarify the characteristics and survival of UCAN diagnosed before the age of 40 using years in a nationwide Japanese cohort study conducted by the Japanese Society for Cancer of the Colon and Rectum.

Methods: We retrospectively analyzed 1212 patients with UCAN treated at 43 institutions in Japan during the period from 1983 to 2020. Patients were categorized as young (<40 years) or non-young (≥40 years). Clinicopathological features, cancer-specific survival (CSS), relapse-free survival (RFS), and survival after recurrence (SAR) were compared.

Results: Young-onset UCAN accounted for 252 patients (20.8%) and showed a shorter interval from UC onset to carcinogenesis (14.0 vs 17.0 years; P < .001), more frequent pancolitis (81.3% vs 74.8%; P = .012), and a higher proportion of poorly differentiated, mucinous, or signet-ring cell carcinoma (20.2% vs 13.3%; P < .001). Five-year CSS was significantly lower in young patients (85.1% vs 89.8%; P = .039), whereas RFS was comparable (86.2% vs 86.3%; P = .750). Minimally invasive surgery (MIS) was independently associated with improved CSS (hazard ratio [HR], 0.593; 95% CI, 0.356-0.987; P = .045). The SAR remained poor in both age groups (23.6% vs 28.5%; P = .468).

Conclusions: When diagnosed in patients aged <40 years, UCAN is characterized by earlier carcinogenesis, extensive disease, and aggressive histology, with worse CSS. The potential role of MIS in improving prognosis warrants further prospective investigation, while the outcome of SAR remains poor irrespective of patient age.