Supplementary Figure 1. Fagan Nomogram analysis. A line is drawn connecting the pre-test probability and the point on the middle vertical line corresponding to the likelihood ratio for the test result, represented by a range of test results (boxes). This line is extended to intersect with the right-hand vertical line, which gives the post-test probability. This point is the new estimate of probability that the patient has the disease. A) Nomogram for post-test probability of having a tumor. B) Nomogram for post-test probability of having a tumor or high-risk adenoma.
ARTICLE ABSTRACT
Background: DNA integrity analysis could represent an alternative approach to the early detection of colorectal cancer. Previously, fluorescence long DNA (FL-DNA) in stools was extracted using a manual approach and analyzed by capillary electrophoresis assay (CE FL-DNA). We aimed to improve diagnostic accuracy using a simpler and more standardized method [Real Time PCR FL-DNA (RT FL-DNA)] for the detection of early malignant lesions in a population undergoing colorectal cancer screening.Methods: From 241 stool samples, DNA was extracted using manual and semiautomatic extraction systems and analyzed using FL-DNA tests by CE and RT assays. The RT FL-DNA approach showed slightly higher sensitivity and specificity compared with the CE FL-DNA method. Furthermore, we compared the RT FL-DNA approach with the iFOBT report.Results: Nonparametric ranking statistics were used to analyze the relationship between the median values of RT FL-DNA and the clinicohistopathologic characteristics. The median values of both variables were significantly higher in patients with cancer than in patients with noncancerous lesions. According to the Fagan nomogram results, the iFOBT and FL-DNA methods provided more accurate diagnostic information and were able to identify subgroups at varying risks of cancer.Conclusions: The combination of the semiautomatic extraction system and RT FL-DNA analysis improved the quality of DNA extracted from stool samples.Impact: RT FL-DNA shows great potential for colorectal cancer diagnosis as it is a reliable and relatively easy analysis to perform on routinely processed stool samples in combination with iFOBT. Cancer Epidemiol Biomarkers Prev; 23(11); 2553–60. ©2014 AACR.
