Colorectal Cancer Screening- New evidence

Colorectal Cancer Screening

1. Colorectal Cancer Screening Wd 23/29 NHSL Dr Rohan Jayawardena Registrar in General Surgery 24/04/20

2. What is Screening Examination of a group of usually asymptomatic people, to detect those with a high probability of having a given disease(preclinical CA) typically by means of an inexpensive diagnostic test Screening program to be successful The disease must be common Simple, acceptable, sensitive, specific, safe & effective screening should be available Accurate & effective investigations & treatment of positive test results should be possible

3. Why Colorectal CA Screening 3 rd most common CA in males & females in UK 40,000 new cases & 16,000 deaths per year 21% CRC - present as emergency admissions Loss of APC gene Early Adenoma Late phase Definitive management is there 5- 10 yrs

4. Survival Rates (Pre-population Screening) Survival rate depends on stage at presentation Earlier the diagnosis, better the prognosis

5. Screening Techniques Stool Based Tests Endoscopic Visualization Radiologic Visualization Blood Based Markers gFOB FIT Stool DNA Test Colonoscopy Sigmoidoscopy Colon Capsule Endoscopy CT Colonography Septin 9

6. Guaiac – based Faecal Occult Blood Haem in the stool contains a pseudoperoxidase ; when exposed to hydrogen peroxide, the pseudoperoxidase releases oxygen which in gFOBt converts the guaiac reagent to a blue colour , giving a ‘positive’ result. Sensitivity in single sample – 25-38% 3 samples – 92-94% False (+) – Food - red meat, melon, grapefruit, cauliflower, cucumber, carrot, cabbage, potato, pumpkin NSAID, UGIB False (-) - High doses of Vitamin C - >250mg

7. Faecal Immunochemical Tests (FIT) Detects small amounts of blood in stool samples through using antibodies specific to human haemoglobin . Uses the same principles as gFOBt But is more sensitive (98 - 100%), specific (95.3%) Requires only a single sample No dietary/medication restrictions needed Need to return within 24h Sensitivity More convenient Higher adherence (than gFOBT & Flexi Sig)

8. Both assess the entire colon But they are more effective for left side lesions ???????????? Compared between gFOB is less effective in FIT & gFOB detecting CRC & Advanced adenomas

9. Stool DNA Test Consists with molecular assays to test for DNA (KRAS) mutations + immunochemical assays (FIT) to test Hb shed in the stools from colorectal neoplasias Requires full stool sample No dietary/medication restrictions needed Frequency of testing – every 3 yrs

10. Flexible Sigmoidoscopy Enable to examine 60 cm of the distal colon Colorectal CA & Adenoma – 70% 94% polyps which are malignant – Located distal to Splenic Flexure More effective in Men – Distal colon lesions common in men than women Flexible Sigmoidoscopy + FOBT/FIT – As a screening program

11. Colonoscopy Definitive test for detection of precancerous adenomas & CRC Most sensitive technique of evaluation Expensive Serious complications (0.2%) Perforation Haemorrhage Reserved for high risk patients

12. Screening Techniques Stool Based Tests Endoscopic Visualization Radiologic Visualization Blood Based Markers gFOB FIT Stool DNA Test Colonoscopy Sigmoidoscopy Colon Capsule Endoscopy CT Colonography Almost similar to colonoscopy in detecting CA & Adenomas > 10mm In every 5 yrs Septin 9 Used in moderate risk patients who refuse screening Sensitivity is low

13. Demographics Strongly related to age – 73% in people => 65 yrs Sporadic cases in young age group – Genetic predisposition & disorders Western life style in UK – Men – 57% Women – 52%

14. Frequency & Age at testing UK – All programs – Every 2 y Netherland study shows same USA – Annually positivity rate + Higher participation for 2 nd round England Wales Age 60 – 74 Northern Ireland Scotland – Age 50 – 74

15. Methods of Population Screening Faecal Occult Blood Testing (+) – invitation for colonoscopy - 5/6 wells – Positive - 1-4/6 – Weakly Positive Faecal Immunochemical Test - Initially used in weakly positive FOBT in Northern Ireland, Scotland, Wales - New test kit introduced in England in June 2019

16. SCREENING PATHWAY

17. Positive Test Result Rates Abnormal FOB Men – 2.5% Women – 1.5% Colonoscopy 80% CA - 12.5% Polyps - 37.5% Normal - 50% Cancers were considered ”Early” ( 32% Dukes A, 30% Dukes B ) Prevent undergoing major resections or from having stomas.

18. Advantages Can diagnose at the early stage of the disease

19. Detection of Benign Diseases

20. Screening in High Risk Categories Hereditary CRC 5% of cases FAP HNPCC MUTYH - associated Polyposis Peutze - Jeghers syndrome (PJS) Juvenile Polyposis syndrome (JPS)

21. No identifiable inherited causative mutation but a clear clustering of cases within a family. 15 – 30% Familial CRC

22. IBD Patients with IBD - Incidence of CRC or dysplasia of 7.7% at 20 years & 15.8% at 30 years following onset of colitis

23. Future Considerations In England in 2018 – Age 50 Bowel scope screening – Flexible Sigmoidoscopy - At age of 55 - Reduced subsequent risk of dying from bowel cancer by 43% and of developing bowel cancer by 33%. - Not yet available everywhere Consider stool DNA assay as a tool for early detection

24. REFERENCES McKigney N, Coyne PE, Bowel cancer screening, Surgery, https:// doi.org /10.1016/j.mpsur.2019.10.013 Beynon, J., & Riddell. (2014). Population screening for colorectal cancer.  INTESTINAL SURGERY I ,  32 (4), 172–178. https:// doi.org /10.1016/j.mpsur.2014.02.002 Scholefield , J. H., & Whines, D. K. (2003). Screening for Colorectal Cancer in the UK: is it Worthwhile?  GENERAL SURGERY I ,  21 (7), III-VI. https:// doi.org /10.1383/surg.21.7.0.15957 Bennett DH, Hardcastle FD.  Screening for colorectal cancer , Recent Advances in Surgery ed. Edinburgh, UK: CHURCHILL LIVINGSTONE; 1995.  Doubeni , C. T., Lamont, J. G., & Elmore, J. Tests for screening for colorectal cancerUpToDate . (2020, March 18). NHS bowel cancer screening (BCSP) programme . (n.d.). Retrieved from https:// www.gov.uk /topic/population-screening- programmes /bowel

25. Thank you