Five years after the start of a nationwide CRC screening program, a decrease in stage II and IV CRC incidence was observed. Patients with screen-detected stage III and stage IV CRC had less extensive disease and improved survival compared to those with clinically-detected CRC.
Inhabitants diagnosed with CRC in 2009-2018 were included. CRC incidence per stage, per year, and detection method (i.e. screen-detected vs clinically-detected) was evaluated. Patient, tumor, and treatment characteristics, and survival of patients with stage III and IV CRC were compared according to detection method.
Screening for colorectal cancer (CRC) aims to decrease CRC incidence and mortality. Biennial fecal immunochemical test screening started in the Netherlands in 2014 for individuals aged 55-75. This study investigated the effect of screening on stage specific incidence, with focus on stage III and IV CRC.
Included were 140,649 CRCs in 136,882 patients. An initial peak of stage I-III CRCs diagnoses after initiation of screening was followed by a continuous decrease within screening-eligible ages. Total CRC incidence remained higher than before screening, although stage II and IV CRC incidence decreased below pre-screening levels. Screen-detected CRCs were significantly more frequently located in the left-sided colon (stage III 43.7% vs 30.9%; stage IV 45.1% vs 36.1%), and the primary tumor resection rate was higher (stage III colon 99.8% vs 99.0%, rectum 97.3% vs 89.7%; stage IV colon 65.4% vs 56.6%, rectum 47.3% vs 33.5%). Patients with screen-detected stage IV CRC had significantly more often single organ metastases (74.5% vs 57.0%, p<0.001) and more frequently received treatment with curative intent (colon 41.3% vs 27.4%, rectum 33.8% vs 24.6%). Overall survival significantly improved for patients with screen-detected CRCs (stage III p<0.001; stage IV p<0.001).