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Table 2 ‘Rectal bleeding’ before diagnosis in colorectal cancer patients, with added sensitivity figures for patients with positive Faecal occult blood test (FOBT) and/or Anaemia. Cohort study with 61,802 patients in primary care (2011–12)

From: Symptoms and signs of colorectal cancer, with differences between proximal and distal colon cancer: a prospective cohort study of diagnostic accuracy in primary care

  N Sensitivity (A) PPV (A) Sensitivity (B) Sensitivity (C) Sensitivity (D)
All Males Females All 95% CI All 95% CI Males Females All 95% CI All 95% CI All 95% CI
Colorectal cancer 94 35 59 17.0% 10.8–25.9 4.0% 2.5–6.4 2.0% 5.1% 39.4% 30.1–49.5 47.9% 38.1–57.9 57.5% 47.4–67.0%
A 16 3 13             
B 37 13 24             
Colon cancer 65 22 43 12.3% 6.4–22.5 2.0% 1.0–4.0 0.7% 2.8% 32.3% 22.2–44.4 41.5% 30.4–53.7 55.4% 43.3–66.8
A 8 1 7             
B 21 6 15             
Colon, proximal cancer 18    -   -     16.7% 5.8–39.2 22.2% 9.0–45.2 38.9% 20.3–61.4
A 0               
B 3 1 2             
Colon, distal cancer 26    23.1% 11.0–42.1 1.5% 0.7–3.3 - 2.4% 46.2% 28.8–64.5 57.7% 39.0–74.5 69.2% 50.0–83.5
A 6 0 6             
B 12 1 11             
Rectal cancer 29 13 16 27.6% 14.7–25.7 2.0% 1.0–4.0 1.3% 2.4% 55.2% 37.6–71.6 62.1% 44.0–77.3 62.1% 44.0–77.3
A 8 2 6             
B 16 7 9             
Colorectal cancer (A), specificity: Specificity 99.4% (95% CI 99.3–99.4), based on 385 patients with 'Rectal bleeding' without cancer, and 60,777 patients with no 'Rectal bleeding' and no cancer
  1. Faecal occult blood test (FOBT) positive: 6 patients with colon cancer and 2 patients with rectal cancer had positive FOBT, performed on clinical grounds but without any mention of rectal bleeding at or after consultation. Of the 6 colon cancer patients with FOBT + , 2 had cancer in the proximal colon, 3 in the distant colon, 1 unknown location. Anaemia': Recorded in 10 patients with colon cancer and 1 with rectal cancer when there was no recording of 'Rectal bleeding' at or after consultation. Of these, 1 patient with colon cancer and the patient with rectal cancer also had FOBT + . Of the 10 colon cancer patients with anaemia, 4 had cancer in the proximal colon, 3 in the distal colon, 3 unknown location. A. Number of patients with rectal bleeding and the specified form of cancer, and sensitivity, specificity and positive predictive value (PPV), based on consultation recordings for all patients. B. Number of patients with rectal bleeding and the specified form of cancer, and sensitivity, based on all recordings from consultation to diagnosis, in colorectal cancer patients. C. Sensitivity based on all recordings of 'Rectal bleeding' and/or FOBT +.  D. Sensitivity based on all recordings of 'Rectal bleeding' and/or FOBT + and/or Anaemia