title: Value of symptoms and additional diagnostic tests for colorectal cancer in primary care: systematic review and meta-analysis.
abstract: OBJECTIVE
  To summarise available evidence on diagnostic tests that might help primary care physicians to identify patients with an increased risk for colorectal cancer among those consulting for non-acute lower abdominal symptoms.
  
  
  METHODS
  PubMed, Embase, and reference screening. Study eligibility criteria Studies were selected if the design was a diagnostic study; the patients were adults consulting because of non-acute lower abdominal symptoms; tests included signs, symptoms, blood tests, or faecal tests. Study appraisal and synthesis methods Two reviewers independently assessed quality with a modified version of the QUADAS tool and extracted data. We present diagnostic two by two tables and pooled estimates of sensitivity and specificity. We refrained from pooling when there was considerable clinical or statistical heterogeneity.
  
  
  RESULTS
  47 primary diagnostic studies were included. Sensitivity was consistently high for age >or=50 (range 0.81-0.96, median 0.91), a referral guideline (0.80-0.94, 0.92), and immunochemical faeces tests (0.70-1.00, 0.95). Of these, only specificity of the faeces tests was good. Specificity was consistently high for family history (0.75-0.98, 0.91), weight loss (0.72-0.96, 0.89), and iron deficiency anaemia (0.83-0.95, 0.92), but all tests lacked sensitivity. None of these six tests was (sufficiently) studied in primary care.
  
  
  CONCLUSIONS
  Although combinations of symptom and results of immunochemical faeces tests showed good diagnostic performance for colorectal cancer, evidence from primary care is lacking. High quality studies on their role in the diagnostic investigation of colorectal cancer in primary care are urgently needed.
authors.affiliation: Department of General Practice, EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, Netherlands.
authors.forename: Petra
authors.initials: P
authors.lastname: Jellema
authors.forename: Daniëlle A W M
authors.initials: DA
authors.lastname: van der Windt
authors.forename: David J
authors.initials: DJ
authors.lastname: Bruinvels
authors.forename: Christian D
authors.initials: CD
authors.lastname: Mallen
authors.forename: Stijn J B
authors.initials: SJ
authors.lastname: van Weyenberg
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Mulder
authors.forename: Henrica C W
authors.initials: HC
authors.lastname: de Vet
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D008875:Middle Aged; D009780:Occult Blood; D010375:Pedigree; D011785:Quality Assurance, Health Care; D012002:Rectal Diseases / Q000209:etiology; D012017:Referral and Consultation; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015431:Weight Loss