Screening for familial colorectal cancer with a sensitive immunochemical fecal occult blood test: a pilot study.
OBJECTIVE
Colonoscopy is empirically recommended as the first choice screening strategy in first-degree relatives of patients with colorectal cancer (CRC). However, this strategy is accepted by less than 40% of the risk population and two-thirds of screened individuals and renders a normal exploration. This pilot study assessed the accuracy of a latex agglutination immunochemical fecal occult blood test (LA-FOBT) for detecting advanced colorectal neoplasm (cancer or adenomatous polyps > or =1 cm in size, with villous pattern or high grade dysplasia) in asymptomatic first-degree relatives of patients with CRC.


METHODS
One hundred and sixty-nine first-degree relatives of 135 index cases were prospectively included. All participants received a sensitive LA-FOBT (hemoglobin detection limit of 50 ng/ml buffer), and were invited to undergo colonoscopy. On the whole, 116 (69%) participants returned LA-FOBT and underwent colonoscopy.


RESULTS
LA-FOBT was positive in 19 of 116 (16%) cases. Colonoscopy detected neoplasms in 49 of 116 (42%) patients: 37 of 116 (32%) were nonadvanced adenomas and 12 of 116 (10%) advanced adenomas. LA-FOBT detected 10 of 12 (83%) advanced adenomas showing a sensitivity, specificity, positive predictive value, and negative predictive value of 83, 91, 53, and 98%, respectively. In patients with positive LA-FOBT, 1.9 colonoscopies were necessary for detecting one advanced adenoma, whereas in case of not performing this test 10 colonoscopies would be needed. Overall, approximately 80% of screening colonoscopies could be precluded using a LA-FOBT.


CONCLUSIONS
One-time screening with LA-FOBT successfully detects advanced colorectal adenomas and may save unnecessary colonoscopies in first-degree relatives of patients with CRC.
Gimeno-García
Antonio Z
AZ
Department of Gastroenterology, University Hospital of Canary Islands, La Laguna, Tenerife, Spain.
Quintero
Enrique
E
Nicolás-Pérez
David
D
Hernández-Guerra
Manuel
M
Parra-Blanco
Adolfo
A
Jiménez-Sosa
Alejandro
A
D000368:Aged; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005192:Family Health; D005260:Female; D006138:Guaiac; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009780:Occult Blood; D010865:Pilot Projects; D012307:Risk Factors; D013030:Spain
D007202:Indicators and Reagents; D006138:Guaiac