Immunochemical faecal occult blood tests in primary care and the risk of delay in the diagnosis of colorectal cancer

Figures & data

Figure 1. Selection of the study group, starting with 538 patients with CRC or adenomas with HGD.^{1. 1}Adenomas with high-grade dysplasia (HGD).

Table I. Immunochemical faecal occult blood test (iFOBT) results in primary care stratified for tumour localizations in 323 patients with CRC and adenomas with HGD.

	Right-side colon n = 88 + 2^1	Left-side colon n = 90 + 9^1	Rectum n = 108 + 16^1	Not specified n = 8 + 2^1	Total n = 294 + 29^1
No iFOBT	18 + 0^1	24 + 2^1	52 + 10^1	2 + 0^1	96 + 12^1
Positive iFOBT	57 + 1^1	61 + 6^1	54 + 6^1	3 + 2^1	175 + 15^1
Negative iFOBT	13 + 1^1	5 + 1^1	2 + 0^1	3 + 0^1	23 + 2^1

Note: ¹Adenomas with high-grade dysplasia (HGD).

Table II. Immunochemical faecal occult blood test (iFOBT) results stratified for the presence of anaemia at the start of investigations in primary care in 323 patients with CRC and adenomas with HGD.

	Anaemia n = 124 + 3^1	No anaemia n = 159 + 25^1	Unknown n = 11 + 1^1	Total n = 294 + 29^1
No iFOBT	23 + 1^1	65 + 10^1	8 + 1^1	96 + 12^1
Positive iFOBT	86 + 2^1	86 + 13^1	3 + 0^1	175 + 15^1
Negative iFOBT	15 + 0^1	8 + 2^1	0 + 0^1	23 + 2^1

Notes: ¹Adenomas with high-grade dysplasia (HGD).

Anaemia was defined as haemoglobin concentration < 134 g/l in men and < 117 g/l in women.

Table III. Symptoms and signs at the start of investigations in primary care and results of immunochemical faecal occult blood tests (iFOBTs) in 323 patients with CRC and adenomas with HGD.

	Rectal bleeding n = 116 + 14^2	Other than rectal bleeding, no anaemia^1 n = 83 + 12^2	Anaemia, no symptoms n = 33 + 1^2	Anaemia with symptoms, rectal bleeding excluded n = 62 + 2^2	All patients n = 294 + 29^2
No iFOBT performed	56 + 5^2	29 + 6^2	0 + 0^2	11 + 1^2	96 + 12^2
IFOBT performed	60 + 9^2	54 + 6^2	33 + 1^2	51 + 1^2	198 + 17^2
of which positive iFOBT	60 + 9^2	46 + 4^2	23 + 1^2	46 + 1^2	175 + 15^2
of which negative iFOBT	0 + 0^2	8 + 2^2	10 + 0^2	5 + 0^2	23 + 2^2

Notes: ¹These were gastrointestinal symptoms n = 80 + 11², or only other symptoms or signs n = 3 + 1².

²Adenomas with high-grade dysplasia (HGD).

Anaemia was defined as haemoglobin concentration < 134 g/l in men and < 117 g/l in women.

Figure 2. Median time from the start of the investigation to clinical diagnosis of CRC and adenomas with HGD, stratified for different symptoms and signs at the start of the investigation and the iFOBT results. Note: For the group “anaemia with symptoms, rectal bleeding excluded” and right-sided tumours, the time to diagnosis was significantly longer (p = 0.008) for those with negative (n = 4) than positive (n = 28) iFOBT at 205 (125–286) days and 85 (55–116) days, respectively. Otherwise splitting into right-sided and left-sided tumours did not affect the results.