Management of pT1 CRC detected on the colorectal cancer screening programme (Basque Country. Spain)

BACKGROUND: The Bowel Cancer Screening Programme (BCSP) started in 2009 with faecal immunochemical test (FIT, with cut-off 20µg/g faeces) every 2 years (for 50-69 year- olds). 2.518.715 people were invited until 2021. Participation rate was 70.4% with 5.3% positive rate and 92.7% adherence to colonoscopy. Colorectal cancer (CRC) detection rate was 2.28 ‰ with 70.6% found in initial stage. The PT1 (stage I) represented 40% of the total cancer detected (4,050 in the overall period). OBJECTIVES: To compare the characteristics and management of pT1 CRC. METHODS: Retrospective cohort study including pT1 CRC Stage I diagnosed after colonoscopy in positive FIT from 2009-2017. Variables: sex, age groups, endoscopic and surgical treatment, CRC recurrence and survival. Chi-square, Logistic Regression, SPSS v.23. RESULTS: Of the 1,523 CRC detected, 585 were detected as pT1 and I stage (38.4%). 73.4% in men and by age group 59% over 60 years-old. 48.5% were treated with surgery and 51.5% with endoscopic resection. No significant differences were found adjusted by sex and age regardless of treatment. In 57.6% of patients under surgery, CRC was not reported by pathological analysis. All cases followed up by colonoscopy with variability in the number of surveillances over time. 4.1% (24) had CRC recurrence with 87% detected in the surveillance, no significant differences regardless of the treatment. 1.5% (9) died due to CRC progression. CONCLUSIONS: Apart from the high number of CRC detected in early stages by the screening Programme, an important number of cases are reported as pT1 CRC. Endoscopic resection is one of the treatments of choice without significant impact either in recurrence of neoplasia or mortality. However, surgical procedure shows overtreatment because of the high number of cases without CRC after the procedure. Therefore, endoscopic resection could be the main choice to treat pT1 CRC. KEY MESSAGES: • Endoscopic resection is one of the treatment of choice without impact in recurrence for the pT1 CRC detected through the BCSP. • The Basque BCSP obtains excellent participation rate, reflected in early detection and treatment of pre and malignant lesions.