华人最佳的胃肠癌症普查方法 (2)叶华青医师,Jeff H. Ye,MD/Ph.D在诊所有很多来年度体检的50岁以上的华人经常询问这个问题。由于现在是信息时代,大家都是有备而来做过一些互联网的搜索
作者:叶医师信箱 时间:2017年04月25日 08:06 查看全文
叶医师信箱发布于 2017-05-16 14:251 楼#
New Blood Test for colon Cancer
ColoVantage® (methylated Septin 9)
Clinical Use
Detect circulating methylated DNA from the SEPT9 gene
Aid in the detection of colorectal cancer (CRC) in patients non-adherent to current testing modalities
Clinical Background
Colorectal cancer (CRC) is the fourth most common cancer in the United States, however, it is the second leading cause of cancer-related deaths.1 The high number of deaths is likely due to the following facts:
The 5-year survival rate dramatically drops from about 90% for patients diagnosed with localized disease to 70% and 12% for those diagnosed with regional and distant stage disease, respectively.2
Only about 40% of patients are diagnosed at an early stage.1
Only about half of adults age 50 and over have been screened.3
Epigenetic changes, including methylation, play a role in the pathogenesis of CRC. Furthermore, DNA methylation occurs in the early stages of tumor development and can serve as a marker for precancerous lesions, such as adenomas. Circulating methylated DNA from the SEPT9 gene, which is involved in cytokinesis and cell cycle control, has been identified as such a marker.
The ColoVantage test detects methylated DNA from the SEPT9 gene in plasma. A case-control study performed at Quest Diagnostics showed that the ColoVantage test is 70% sensitive for CRC detection at a specificity of 89%.4 ColoVantage has successfully detected cancer at all stages; however, the number of patients at each stage of cancer was too small to derive stage-specific sensitivity data. A similar test demonstrated a sensitivity of 67% and a specificity of 88% in a prospective study of almost 8000 people.5
Current screening methods are either moderately invasive or require collection of a stool sample. Special patient preparation steps are often involved. These, among other things, may be barriers to screening.
ColoVantage represents an important medical advancement in that it is a plasma-based test that requires no patient preparation. A physician may order the ColoVantage test for screen-eligible patients who have previously avoided established colorectal cancer screening methods such as colonoscopy, fecal occult blood tests, and fecal immunochemical tests (FITs). A patient whose ColoVantage test result is positive may be at increased risk for colorectal cancer and further evaluation should be considered. ColoVantage is not a replacement test for colonoscopy.
Method
Real-time polymerase chain reaction (PCR)-based measurement of methylated SEPT9 DNA
Alias: methylated septin 9 DNA, methylated SEPT9 DNA
Interpretive Information
A patient whose ColoVantage test result is positive may be at increased risk for colorectal cancer and further evaluation should be considered.
References
American Cancer Society. Statistics for 2012. American Cancer Society Web site. Available at: http://www.cancer.org/Research/CancerFactsFigures/index. Accessed October 3, 2012.
Howlader N, Noone AM, Krapcho M, et al (eds). SEER Cancer Statistics Review, 1975-2009. National Cancer Institute SEER Web site. Available at: http://www.seer.cancer.gov/statfacts/html/colorect.html. Updated November 2011. Accessed October 3, 2012.
Shapiro JA, Seeff LC, Thompson TD, et al. Colorectal cancer test use from the 2005 national health interview survey. Cancer Epidemiol Biomarkers Prev. 2008;17:1623-1630.
Data on file at Quest Diagnostics.
Rösch T, Church T, Osborn N, et al. Prospective clinical validation of an assay for methylated SEPT9 DNA for colorectal cancer screening in plasma of average risk men and women over the age of 50 [abstract]. Gut. 2010;59(suppl III):A307.
This test was developed and performance characteristics have been determined by Quest Diagnostics Nichols Institute. Performance characteristics refer to the analytical performance of the test.
作者:叶医师信箱 时间:2017年04月25日 08:06 查看全文