Treatment of clinical T1 rectal cancer in the Netherlands; a population-based overview of clinical practice

Local excision is increasingly used as an alternative treatment for radical surgery in patients with early stage clinical T1 (cT1) rectal cancer. This study provides an overview of incidence, staging accuracy and treatment strategies in patients with cT1 rectal cancer in the Netherlands. Patients with cT1 rectal cancer diagnosed between 2005 and 2018 were included from the Netherlands Cancer Registry. An overview per time period (2005-2009, 2010-2014 and 2015-2018) of the incidence and various treatment strategies used, e.g. local excision (LE) or major resection, with/without neoadjuvant treatment (NAT), were given and trends over time were analysed using the Chi Square for Trend test. In addition, accuracy of tumour staging was described, compared and analysed over time. In total, 3033 patients with cT1 rectal cancer were diagnosed. The incidence of cT1 increased from 540 patients in 2005–2009 to 1643 patients in 2015–2018. There was a significant increased use of LE. In cT1N0/X patients, 9.2% received NAT, 25.5% were treated by total mesorectal excision (TME) and 11.4% received a completion TME (cTME) following prior LE. Overall accuracy in tumour staging (cT1 = pT1) was 77.3%, yet significantly worse in cN1/2 patients, as compared to cN0 patients (44.8% vs 77.9%, respectively, p