Experience with a two-tier reflex gFOBT/FIT strategy in a national bowel screening programme

Abstract

Objectives To evaluate a two-tier reflex guaiac-based faecal occult blood test (gFOBT)/faecal immunochemical test (FIT) algorithm in screening for colorectal cancer. Setting Fourth screening round in NHS Tayside (Scotland). Methods gFOBT were sent to 50-74-year-olds. Participants with five or six windows positive were offered colonoscopy. Participants with one to four windows positive were sent a FIT and, if positive, were offered colonoscopy. Participants providing an untestable gFOBT were sent a FIT and, if positive, were offered colonoscopy. Outcomes following positive results, cancer stages and key performance indicators were assessed. Results Of 131,885 invited, 73,315 (55.6%) responded. There were 66,957 (91.3%) negative, 241 (0.3%) strong positive, 5230 (7.1%) weak positive and 887 (1.2%) untestable results. The 241 participants who had five or six windows positive had more cancers than those positive by other routes: only 3 of the 30 cancers (9.7%) were Dukes' A. Among the 983 positive results from the weak positive gFOBT then positive FIT route, there were fewer cancers and more normal colonoscopies, but more adenomas than in the group with a strong positive gFOBT. In those with an untestable gFOBT, 77 had a positive FIT result, with fewer true and more false positive results than in the other groups. Fewer males had cancer and stages were earlier than in females, but more had adenoma. The detection rate for cancer was 0.18% and the PPV for cancer and all adenomas was 41.3%. Conclusions The algorithm and FIT following a weak positive gFOBT have advantages. FIT following an untestable gFOBT warrants review.

Use of a faecal immunochemical test narrows current gaps in uptake for sex, age and deprivation in a bowel cancer screening programme

“…10 In our assessment of a recent evaluation of FIT as a first-line test in two rather different NHS Boards in Scotland (NHS Tayside and NHS Ayrshire & Arran), we documented and compared uptake with that obtained contemporaneously in two other NHS Boards (NHS Fife and NHS Forth Valley), selected for their similarity to NHS Tayside and NHS Ayrshire & Arran, respectively, and also before and after the evaluation in all four NHS Boards. 11 The overall uptake in the two evaluation NHS Boards that participated in the study rose by 5.2% and 6.0% during the use of FIT, but then fell to values similar to those previously seen when the current gFOBT/FIT algorithm used in Scotland 12 was reinstituted. The two NHS Boards in which FIT was not used had small, random changes in uptake over time, but did not have the important rise in participation seen with use of FIT.…”

Interval cancers in a national colorectal cancer screening programme

“…for those who had one to four of the six windows positive in the gFOBT), a qualitative faecal immunochemical test (FIT) (Hema-Screen SPECIFIC, Immunostics Inc., Ocean, New Jersey, USA) was employed. 7 This was based on work that had demonstrated improved performance of this novel two-tier reflex gFOBT/FIT screening algorithm in terms of fewer false positives. 8 Moreover, although some resident in the three NHS Boards participated one, two or three times in the demonstration pilot, particularly with the age range extension, this study can be considered to be concerned with prevalence round screening.…”

A future for faecal haemoglobin measurements in the medical laboratory

“…The results attained continue to show the significant benefits of this approach. 4,5 Other countries, for example, France, also use gFOBT in a successful nationwide screening programme. 6 However, the interest stimulated in laboratory medicine by the advent of the UK screening programmes, along with significant publicity in the media and the intensive efforts of charities involved in this area, led to assessment of whether gFOBT were appropriate for investigation of those individuals with symptoms of colorectal disease.…”