Next-Generation Stool DNA Test Accurately Detects Colorectal Cancer or Large Adenomas
Menée sur des échantillons de selles prélevés sur 252 patients atteints d'un cancer colorectal, 133 patients présentant des adénomes supérieurs à 1 cm et 293 témoins dont les résultats d'une coloscopie étaient normaux, cette étude rétrospective évalue la capacité d'un test de nouvelle génération, basé sur la recherche de l'ADN de 6 gènes, à détecter un cancer colorectal ou des adénomes de grande dimension
Technical advances have led to stool DNA (sDNA) tests that might accurately detect neoplasms on both sides of the colorectum. We assessed colorectal neoplasm detection by a next-generation sDNA test and effects of covariates on test performance. We performed a blinded, multicenter, case-control study using archived stool samples collected in preservative buffer from 252 patients with colorectal cancer (CRC), 133 with adenomas ≥ 1 cm, and 293 individuals with normal colonoscopy results (controls); 2/3 were randomly assigned to a training set and 1/3 to a test set. The sDNA test detects 4 methylated genes, a mutant form of KRAS, and the -actin gene (as a reference value) using quantitative, allele-specific, real-time target and signal amplification; it also quantifies hemoglobin. We used a logistical model to analyze data. The sDNA test identified 85% of patients with colorectal cancer (CRC) and 54% of patients with adenomas ≥ 1 cm with 90% specificity. The test had a high rate of detection for all non-metastatic stages of CRC (aggregate 87% detection rate for CRC stages I–III). Detection rates increased with adenoma size: 54% ≥ 1 cm, 63% >1 cm, 77% >2 cm, 86% >3 cm, and 92% >4 cm (P <.0001). Based on receiver-operating characteristic analysis, the rate of CRC detection was slightly greater for the training than the test set (P =.04), whereas the rate of adenoma detection was comparable between sets. Sensitivities for detection of CRC and adenoma did not differ with lesion site. Early-stage CRC and large adenomas can be detected, throughout the colorectum and with high levels of accuracy, by the sDNA test. Neoplasm size, but not anatomical site, affected detection rates. Further studies are needed to validate the findings in a larger population and optimize the sDNA test.
Gastroenterology , résumé, 2010