Background: We aimed to evaluate the impact of advanced medical therapies (biologicals and small molecules) on time to colectomy and oncological outcomes in ulcerative colitis (UC).

Methods: This cohort study included UC patients who underwent colectomy between 2003 and 2022 at 2 referral centers in Belgium and the Netherlands. Exposure was the use of advanced medical therapies. Primary outcomes were time to colectomy and colorectal cancer (CRC) rate, compared between 4 periods: P1 (2003-2007), P2 (2008-2012), P3 (2013-2017), and P4 (2018-2022). Secondary outcomes were oncological outcomes, including incidental cancers found unexpectedly in resection specimens or during endoscopic follow-up for medication switch.

Results: Among 716 patients, the usage of advanced therapies increased from 36.8% in P1 to 89.7% in P4 (P < .0001). Median time to colectomy remained comparable (P1: 7.1 years [interquartile ranges (IQR), 2.8-12.9] vs P4: 7.2 years [IQR, 2.7-14.6]; P = not significant). Colectomy and colorectal cancer was diagnosed in 72 (10.1%) patients, with no significant change over time (P = .44). Proportion of CRC was lower in patients treated with advanced therapies (4.7% vs 23.6%, P < .0001) and related to a shorter follow-up (median 6.1 vs 10.3 years, P < .0001). Advanced therapy patients had higher incidental cancer rates (37.5% vs 8.3%, P = .002), which was associated with reduced CRC-related survival (HR for CRC-related death: 3.3, 95% CI 1.17-9.4; P = .02).

Conclusions: Despite increased usage of advanced medical therapies, time to resection and CRC rates have remained unchanged in UC patients undergoing colectomy over the past 2 decades. Advanced therapy patients had higher incidental cancers rates, associated with decreased CRC survival. Awareness of timely colectomy is crucial for this group.