1. Diagnostic accuracy systematic review of rectal bleeding in combination with other symptoms, signs and tests in relation to colorectal cancer Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T. Marleen Olde Bekkink Erasmus student, clinical research fellow Dept of General Practice Radboud University Nijmegen Medical Centre, the Netherlands 8th July 2009

2. 2 Background 2 *1. Fijten GH et al. 1994 *Mant A. et al. 1988 Incidence of CRC in patients with rectal bleeding General population: < 1 per 1000 1 people General practice: 2-11 per 100 1 patients Secondary care: 36 per 100 1 referred patients 1 st selection by patient 2 nd selection by GP Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T.

3. Methods - Study protocol Inclusion criteria Population * Patients recruited from primary care population * Rectal bleeding and associated symptoms Study design * Observational cohort studies Reference standard and follow up *Colonoscopy *Flexible/ rigid sigmoidoscopy (and barium enema) *Questionnaire/ follow up only Outcome measures * Data must allow construction of 2x2 tables 3 Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T.

4. 4 Methods – Inclusion of articles Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T. Potentially relevant citations (n=1534) Excluded after scanning of citation or abstract (n=1470) Full text retrieved (n=64) Excluded (n=56) Reason for exclusion: Setting not in general practice (n = 23) Screening study (n = 5) Case control study (n = 5) Data not extractable from 2x2 table (n = 15) Other (n=8) Included studies (n=8)

5. 55 Methods – Characteristics of the included studies No of patients included: 2323 Prior CRC Weighted average: 7.0 % Median : 8.1 % Eight included studies (1988 - 2006) Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T. Included articles: GP setting NoStudy IDPrior 1du Troit 20065.7% (15/265) 2Ellis 20053.4% (11/319) 3Fijten 19953.3% (9/269) 4Heintze 20054.8% (23/476) 5Mant 198811% (16/145) 6Metcalf 19968.1% (8/99) 7Norrelund 1996 15.4% (32/208) 14.1% (22/156) 8Wauters 20007.0% (27/386)

6. 66 Methods – Quality assessment Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T.

7. 77 Methods- Data extraction Extraction in 2x2 tables to calculate LR+ Metcalf 1996 prior 8/99 Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T. Sign/ symptom/ characteristicsNo of patients% populationNo cancers Dark red blood loss3131%3 Weight loss1515%2 Blood mixed with stool4646%5

8. 8 Results- Pooled positive likelihood ratios 8 Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T. Patient characteristicsNo of studies No of patientsPooled PLR (95% CI) Male512531.21(1.00-1.46) Age <40y27450.32(0.05-2.21) Age ≥ 60y61760 2.79 (2.00-3.90) Family history colorectal cancer38661.05(0.16-6.88) Signs/ symptoms No of studies No of patientsPooled PLR (95% CI) Dark red blood49491.37(0.59-3.30) Weight loss71737 1.89 (1.03-3.07) Abdominal pain717390.94(0.19-1.59) Blood mixed with the stool51225 1.91 (0.75-5.51) Changed bowel habit51254 1.92 (0.54-3.57) Perianal symptoms- pain on defecation24110.49(0.25-0.97) Diagnostic testsNo of studies No of patients Pooled PLR (95% CI) Anaemia (Hb ♀ < 12..0 g/dL ♂ <13.3 g/dL) 2700 3.67 (1.30-10.35) Rectal palpation-haemorrhoid 2 3540.51(0.09-2.97)

9. 99 Discussion Limitations of sub studies - Reference standard ≠ gold standard Limitations of the review - Internal validity Reference categories - External validity Incidence of colorectal cancer Edited image ( MO ) Original: Mayo Foundation for Medical Education and Research Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T.

10. 10 Conclusion Value of the review Implications for clinical practice guidelines  Predictive value of rectal bleeding low-moderate  Alarm symptoms yield only moderate likelihood ratios Further studies required calculating independent values using a multivariable analysis Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T.

11. 11 Questions Thank you!