Fecal test finds cancers, misses adenomas.
In addition, the fecal immunochemical test (FIT) performed poorly in identifying patients with adenomas, some of which are precancerous, suggesting that reliance on this fecal test would diminish opportunities to prevent cancers.
There was no difference in the stage of tumors identified by the two methods in an interim analysis of a 10-year clinical trial that will not be completed until 2021, said Dr. Enrique Quintero of the department of gastroenterology, Hospital Uni-versitario de Canarias, Tenerife, Spain, and his associates.
In the randomized, controlled trial, the researchers had hypothesized that FIT screening every 2 years would prove noninferior to one-time colonoscopy "with respect to a reduction in mortality related to colorectal cancer among average-risk subjects" after 10 years. They reported these interim results after the first "round" of screening was completed in 53,302 subjects.
The study involved men and women aged 50-69 years in eight regions of Spain who were invited to undergo screening by FIT (26,599 subjects) or colonoscopy (26,703) at 15 tertiary care hospitals. Only 5,649 of the subjects randomly assigned to colonoscopy agreed to that screen, and only 4,953 actually underwent colonoscopy; another 1,628 opted for FIT instead. This yielded a participation rate of only 24.6% for colonoscopy
A total of 9,353 subjects assigned to FIT agreed to that screen, and 8,983 of them actually underwent FIT; another 106 opted for colonoscopy instead. This yielded a participation rate of 34.2% for FIT.
Thus, participation rates were very low in both groups, but subjects in the FIT group were more likely to participate than were those in the colonoscopy group. This may offset any apparent advantage with colonoscopy, they said.
Colorectal cancer was detected in a similar number of subjects in both groups in this first round of screening. In the intention-to-screen analysis, colorectal cancer was detected in 30 subjects (0.1 %) in the colonoscopy group and 33 subjects (0.1%) in the FIT group (N. Engl. J. Med. 2012; 366:697-706).
In an analysis of screening that was actually performed, colorectal cancer was detected in 27 subjects (0.5%) in the colonoscopy group and 36 subjects (0.3%) in the FIT group.
Tumor stage was similar for the two groups. However, colonoscopy was superior to FIT in rate of detection of both advanced adenomas (odds ratio, 4.32) and nonadvanced adenomas (OR, 25.98).
Major complications developed in 24 subjects (0.5%) in the colonoscopy group: Twelve subjects experienced bleeding and one had a bowel perforation. No major complications developed in the FIT group, except among some subjects with positive findings who then underwent colonoscopy; eight of
them experienced bleeding from the colonoscopy.
The primary outcome measure of the trial - the reduction in colorectal cancer mortality after 10 years - cannot be assessed yet.
This study was supported by the Asociacion Espanola contra el Cancer, Instituto de Salud Carlos III, FEDER funds, Agencia. de Gestio d'Ajuts Universitaris i de Recerca, Obra Social de Kuxta, Diputacion Foral de Gipuzkoa, Departmento de Sanidad del Gobierno Vasco, EITB-Maratoia, Accion Trans versal contra el Cancer del CIBERehd, Direcion Xeral de Innovacion e Xestion da Saude Publica, Conselleria de Sanidade, and Xunta de Galicia. Eiken Chemical of Japan, with Palex Medical and Biogen Di agnostics, donated supplies used for FIT.
BY MARY ANN MOON
FROM THE NEW ENGLAND JOURNAL OF MEDICINE
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|Author:||Moon, Mary Ann|
|Publication:||Internal Medicine News|
|Date:||Mar 15, 2012|
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