Comparison of faecal M2-PK and FIT in a population-based bowel cancer screening cohort.
BACKGROUND
Screening for colorectal cancer improves outcomes and is cost effective. Stool-based tests have the highest participation rates in screening programmes. Their efficacy is limited by the relatively low sensitivity and specificity compared with colonoscopy. Stool levels of M2-PK, a dimeric form of the enzyme pyruvate kinase, correlate with colorectal cancer and neoplasia. A combination of stool markers may enhance screening performance; however, it remains to be determined whether an additional test would affect participation rates negatively.


OBJECTIVE
The aim of this study was to assess the performance of faecal M2-PK and faecal immunochemical test (FIT) and their combined effect in a screening programme.


METHODS
Within round 2 of our biennial FIT-based pilot, all invitations additionally included an M2-PK kit. A FIT greater than 100 ngHb/ml and/or an M2-PK greater than 4 U/ml were considered positive. FIT-positive or M2-PK-positive patients were offered a colonoscopy.


RESULTS
In all, 1800 combined M2-PK and FIT invites were sent out, and 879 (49%) samples were analysed. Overall positivity was 27% (n=245). Only 23 (2.6%) patients were positive for both tests. In all, 186 (88%) screening colonoscopies were performed. The adenoma detection rate for M2-PK-positive patients (n=157) was significant at 25% (n=40), and 3% (n=5) had advanced lesions. In FIT-positive patients (n=51), the adenoma detection rate was 29% (n=15), with significantly more, 21% (n=11), having advanced lesions (P<0.001, confidence interval 0.117-0.156). Had FIT only been tested, 70% (n=35) fewer patients would have had polyps removed.


CONCLUSIONS
The addition of M2-PK in a biennial bowel screening programme is acceptable to patients, feasible and detects additional adenomas, potentially at an earlier stage.
Department of Gastroenterology & Clinical Medicine, Trinity Centre, Tallaght Hospital, Trinity College Dublin, Dublin, Ireland.
Ronan
R
Leen
Chun
C
Seng-Lee
Grainne
G
Holleran
Colm
C
O'Morain
Deirdre
D
McNamara
D000236:Adenoma / Q000201:enzymology* / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002352:Carrier Proteins / Q000032:analysis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000473:pathology; D055088:Early Detection of Cancer / Q000379:methods*; D005240:Feasibility Studies; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D008875:Middle Aged; D009367:Neoplasm Staging; D010342:Patient Acceptance of Health Care; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011770:Pyruvate Kinase / Q000032:analysis*; D013963:Thyroid Hormones / Q000032:analysis*; D000097810:Thyroid Hormone-Binding Proteins
D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D008565:Membrane Proteins; D011770:Pyruvate Kinase; D013963:Thyroid Hormones; D000097810:Thyroid Hormone-Binding Proteins