• colorectal neoplasms
• delayed diagnosis
• neoplasm metastasis

• anticipated delay
• cancer awareness
• cancer symptoms
• colorectal cancer
• knowledge
• risk factors

Colorectal cancer remains a significant cause of morbidity and mortality, even despite curative treatment. A significant proportion of patients present emergently and have poorer outcomes compared to elective presentations, independent of TNM stage. In this systematic review and meta-analysis, differences between elective/emergency presentations of colorectal cancer were examined to determine which factors were associated with emergency presentation. A literature search was carried out from 1990 to 2018 comparing elective and emergency presentations of colon and/or rectal cancer. All reported clinicopathological variables were extracted from identified studies. Variables were analysed through either systematic review or, if appropriate, meta-analysis. This study identified multiple differences between elective and emergency presentations of colorectal cancer. On meta-analysis, emergency presentations were associated with more advanced tumour stage, both overall (OR 2.05) and T/N/M/ subclassification (OR 2.56/1.59/1.75), more: lymphovascular invasion (OR 1.76), vascular invasion (OR 1.92), perineural invasion (OR 1.89), and ASA (OR 1.83). Emergencies were more likely to be of ethnic minority (OR 1.58). There are multiple tumour/host factors that differ between elective and emergency presentations of colorectal cancer. Further work is required to determine which of these factors are independently associated with emergency presentation and subsequently which factors have the most significant effect on outcomes.

The implementation of a colorectal cancer (CRC) screening programme may increase the awareness of Primary Care Physicians, reduce the diagnostic delay in CRC detected outside the scope of the screening programme and thus improve prognosis.

To determine the effect of implementation of a CRC screening programme on diagnostic delays and prognosis of CRC detected outside the scope of a screening programme.

We performed a retrospective intervention study with a pre-post design. We identified 322 patients with incident and confirmed CRC in the pre-implantation cohort (June 2014 – May 2015) and 285 in the post-implantation cohort (June 2017 - May 2018) in the Cancer Registry detected outside the scope of a CRC screening programme. In each patient we calculated the different healthcare diagnostics delays: global, primary and secondary healthcare, referral and colonoscopy-related delays. In addition, we collected the initial healthcare that evaluated the patient, the home location (urban/rural), and the CRC stage at diagnosis. We determined the two-year survival and we performed a multivariate proportional hazard regression analysis to determine the variables associated with survival.

We did not detect any differences in the patient or CRC baseline-related variables. A total of 20.1% of patients was detected with metastatic disease. There was a significant increase in direct referral to colonoscopy from primary healthcare (25.5%, 35.8%; P = 0.04) in the post-implantation cohort. Diagnostic delay was reduced by 24 d (106.64 ± 148.84 days, 82.84 ± 109.31 d; P = 0.02) due to the reduction in secondary healthcare delay (46.01 ± 111.65 d; 29.20 ± 60.83 d; P = 0.02). However, we did not find any differences in CRC stage at diagnosis or in two-year survival (70.3%; P = 0.9). Variables independently associated with two-year risk of death were age (Hazard Ratio-HR: 1.06, 95%CI: 1.04-1.07), CRC stage (II HR: 2.17, 95%CI: 1.07-4.40; III HR: 3.07, 95%CI: 1.56-6.08; IV HR: 19.22, 95%CI: 9.86-37.44; unknown HR: 9.24, 95%CI: 4.27-19.99), initial healthcare consultation (secondary HR: 2.93, 95%CI: 1.01-8.55; emergency department HR: 2.06, 95%CI: 0.67-6.34), hospitalization during the diagnostic process (HR: 1.67, 95%CI: 1.17-2.38) and urban residence (HR: 1.44, 95%CI: 1.06-1.98).

Although implementation of a CRC screening programme can reduce diagnostic delays for CRC detected in symptomatic patients, this has no effect on CRC stage or survival.

• Colorectal cancer
• Population based screening
• Primary healthcare
• Diagnostic delay
• Prognosis

• Colonoscopy
• Colorectal Neoplasms/diagnosis
• Colorectal Neoplasms/epidemiology
• Delayed Diagnosis
• Early Detection of Cancer
• Humans
• Prognosis
• Retrospective Studies

Artificial intelligence (AI) is a branch of computer science. As a new technological science, it mainly develops and expands human intelligence through the research of intelligence theory, methods and technology. In the medical field, AI has bright application prospects (for example: imaging, diagnosis and treatment). The exploration of robotic gastroscopy and colonoscopy systems is not only a bold attempt, but also an inevitable trend of AI in the development of digestive endoscopy in the future. Based on the current research findings, this article summarizes the research progress of colonoscopy, and looking forward for the application of AI in colonoscopy.

• Artificial intelligence
• Colonoscopy
• Application
• Gastrointestinal
• Endoscopy

• symptomatic presentations
• primary care
• emergency diagnosis
• colorectal cancer
• data-linkage study

• Abdominal Pain/etiology
• Adenocarcinoma/complications
• Adenocarcinoma/diagnosis
• Adenocarcinoma/therapy
• Aged
• Anemia/etiology
• Colorectal Neoplasms/complications
• Colorectal Neoplasms/diagnosis
• Colorectal Neoplasms/therapy
• Delayed Diagnosis
• Early Detection of Cancer
• Emergencies
• England/epidemiology
• Female
• Gastrointestinal Hemorrhage/etiology
• Humans
• Male
• Middle Aged
• Organ Specificity
• Primary Health Care
• Referral and Consultation/statistics & numerical data
• Registries
• Symptom Assessment

• 18525 Cancer Research UK
• 18180 Cancer Research UK
• C48748/A18667 Cancer Research UK
• 18667 Cancer Research UK
• 11700 Cancer Research UK
• A18180 Cancer Research UK