Abstract
INTRODUCTION: National colorectal cancer screening, utilising a faecal occult blood test (FOBT), is now well established in the UK. The aim of this study was to define the screening characteristics of patients presenting to secondary care with symptoms of colorectal cancer and to assess the effect of screening outcome on subsequent symptomatic presentation. METHODS: This was a retrospective analysis of all patients of screening age presenting within one calendar year in a tertiary trust via a two-week wait (2WW) pathway owing to suspicion of colorectal cancer. Colorectal cancer related outcomes were compared between patients in the cohort who had previously accepted bowel cancer screening and patients who had previously declined bowel cancer screening. The primary endpoint was overall incidence of colorectal neoplasia. Secondary endpoints included incidence of colorectal malignancy, cancer related mortality, cancer related outcomes and polyp related outcomes. RESULTS: Overall, 2,227 patients presented via the 2WW pathway; 955 were aged 60-75 years. Among the latter, 411 (43%) had been screened previously and had a negative FOBT, and 544 (57%) had declined screening. Incidence of colorectal neoplasia did not differ between the two groups (113 [27%] vs 143 [26%], p=0.7). Of those with a negative FOBT and subsequent symptomatic presentation, 16 (3.9%) were diagnosed with a colorectal malignancy compared with 36 (6.6%) of those who declined screening and had subsequent symptomatic presentation (relative risk: 1.7, 95% confidence interval: 0.96-3.02, p=0.08). There were no differences between the two groups with regard to TNM (tumour, lymph nodes, metastasis) stage, Dukes' stage, metastases, number of polyps or cancer related mortality (median follow-up duration: 20 months). CONCLUSIONS: The incidence of colorectal neoplasia was similar among patients who previously had a negative FOBT and those who declined screening. There was a higher incidence of colorectal cancer detected among those who declined screening but it did not reach statistical significance. All other cancer and polyp outcomes were similar between the groups.