Colon Cancer: Likelihood Ratios

Introduction: None written.

Prevalence

The likelihood ratios of findings for Colon Cancer are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Finding	+LR	-LR	Comments, Study
Colonoscopy	6.8	0.1	Sensitivity differs for adenoma size (<5 mm 75%, 6-9mm 85%, >10mm 95%). Study: USPSTF Modeling Report https://www.uspreventiveservicestaskforce.org/uspstf/document/modeling-report1/colorectal-cancer-screening
Fecal Occult Blood Duplicate	5.9	0.1	immunoassay-based test (note the very high sensitivity here) this was only in secondary referral clinics (probable bias?) Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Fecal Occult Blood Duplicate	5.4	0.3	guaiac-based test (note much higher sensitivity here compared to other studies) Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221

Good Negative Likelihood Ratio

Finding	+LR	-LR	Comments, Study
Secondary Screening Referral Guideline	1.6	0.2	At least one of the following: Rectal bleeding with a change in bowel habit to looser stools and/or increased frequency of defecation persistent for 6 weeks. Age threshold: all ages. Change in bowel habit as above without rectal bleeding and persistent for 6 weeks. Age threshold: over 60 years. Rectal bleeding persistently without anal symptoms. Age threshold: over 60 years. A definite palpable right-sided abdominal mass. Age threshold: all ages. A definite palpable rectal mass (not pelvic). Age threshold: all ages. Unexplained iron deficiency anaemia. In men: below 11g/dl, all ages. In women: below 10 g/dl, post menopausal. Study:* BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Age Duplicate	1.8	0.3	Age > 60 Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Age Duplicate	1.4	0.3	Age > 50 Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221

Good Positive Likelihood Ratio

Finding	+LR	-LR	Comments, Study
Fecal Occult Blood Duplicate	4	0.8	6-sample Study: Ann Intern Med. 2005 Jan 18;142(2):81-5. PMID: 15657155
Age Duplicate	2.4	0.6	Age > 70 Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Rectal Mass	2.3	0.8	note that sens for abdominal mass = 4% Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221

Poorly Diagnostic Findings

Finding	+LR	-LR	Comments, Study
Fecal Occult Blood Duplicate	1.7	1	single sample from DRE Study: Ann Intern Med. 2005 Jan 18;142(2):81-5. PMID: 15657155
Family History of Colon Cancer	1.8	0.9	Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Weight	1.8	0.9	Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Diarrhea	0.7	1.1	Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Constipation	0.5	1.2	Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Rectal bleeding	1.3	0.8	for "dark blood" sens=35% / spec=85%; for "mixed with stool" sens=51% / spec=71% Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Changes in Bowel Habits	1.3	0.8	Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221
Gender	1.4	0.7	male Study: BMJ. 2010 Mar 31;340:c1269 PMID: 20360221

Findings With Unspecified Accuracy

No accuracy specified.

Aside from colon cancer, other GI pathology, liver disease and HIV should be considered.

Study: PMID: 16614996

Alazmi W; Bustamante M; O'loughlin C; Gonzalez J; Raskin JB

Dig Dis Sci. 2006 Apr;51(4):732-6.

No accuracy specified.

Carcinoembryonic antigen

Study: no study specified.