Non-Polyploid Colon Regions Are Linked To Colorectal Cancer - And More Common Than Previously Thought
March 14th, 2008 | by admin |Flat,non-polyploid colorectal neoplasms (NP-CRNs) are difficult to detect,but when examined, they appear to be common. Additionally they may havea stronger association with colorectal cancer than polyps, which aremore routinely observed in examination, according to a study publishedon March 5, 2008 in JAMA
Colorectal cancer, sometimessimply called colon cancer, encompasses cancerous growths in the largeintestines and appendix. It is the second leading cause of cancer deathin the United States. Prevention strategies have focused on detectingand removing polyploid neoplasms, which are abnormal growths resemblingpolyps. More recently, however, it has been shown that colorectalcancer can develop from NP-CRNs, which are flat or depressedinshape. These can be more difficult to detect, according to the authorsof the study: “Nonpolypoid colorectalneoplasms are more difficult to detect by colonoscopy or computedtomography colonography because the subtle findings can be difficult todistinguish from those of normal mucosa [membrane]. As compared withsurrounding normal mucosa, NP-CRNs appear to be slightly elevated,completely flat, or slightly depressed.”
Since information islimited regarding the true significance of NP-CRNs in colorectal cancerdevelopment, Roy M. Soetikno, M.D.,M.S., and colleagues with the Veterans Affairs Palo Alto Health CareSystem, Palo Alto, California, investigated data from 1,819 patientsundergoing elective colonoscopy, in the hope of estimating thefrequency of NP-CRNs and to characterize the relationship of NP-CRNs tocolorectal cancer.
Patients were also classified into subgroups according to theirsituations: the screening group, of asymptomaticpatients who had undergone average risk-screening colonoscopies; the surveillancegroup, who had a personal or hereditary history of colorectal cancer;or the symptomaticgroup, who showed symptoms and indications associated with colorectalneoplasms, including anemia, rectal bleeding, constipation, diarrhea,positive results from a fecal occult blood test, weight loss, abdominalpain, and inflammatory bowel disease.
In the whole group, NP-CRNs were present in 9.35% of patients.According to subpopulation, the screening group showed 5.84%,surveillance showed 5.84%, and symptomatic showed 6.01%. In cancersthat had not spread, or had spread in the tissue beneath the mucousmembrane the overall prevalence was 0.82%, while prevalence in thescreening population was 0.32%. It was also observed in thesurveillance and screening populations.
Overall, NP-CRNs were almost 10 times more likely to contain canceroustissue than polyploid lesions, regardless of size. Thedepressed type of NP-CRNs showed the highest risk (33%.) NP-CRNscontaining cancer were generally smaller in diameter when compared withpolyploid cancerous regions.
“In conclusion, inthis population of patients at a single Veterans Affairs hospital,NP-CRNs were a relatively common finding during colonoscopy. They weremore likely to contain carcinoma compared with polypoid neoplasms,independent of lesion size. Recent studies have pointed out differencesin the genetic mechanisms underlying nonpolypoid and polypoidcolorectal neoplasms. Future studies on NP-CRNs should further evaluatewhether the diagnosis and removal of NP-CRNs has any effect on theprevention and mortality of colorectal cancer and particularly focus ontheir genetic and protein abnormalities,” write the authors.
Editorial: Nonpolypoid Colorectal Neoplasia in the UnitedStates
David Lieberman, M.D., of Oregon Health& Science University, Portland VA Medical Center, Portland,Ore.,contributed an additional editorial in which he comments on thefindings of Soetikno and colleagues. “[Nonpolypoidcolorectal neoplasms] may be biologically distinct from polypoidlesions and appear to be more likely to harbor malignant features.Detection and complete removal at colonoscopy may be challenging. Thecurrent study emphasizes the importance of quality in the performanceof colonoscopy,” he writes. “The optimal methods for enhancingcolonoscopic imaging of NP-CRNs are uncertain. … Additional studies areneeded to determine whether imaging modalities such as computedtomography colonography will be able to detect NP-CRNs. Finally,longitudinal studies are needed to determine whether patients withNP-CRNs require more intensive colonoscopic surveillance compared withpatients with polypoid lesions of similar size and histology.”
Prevalence of Nonpolypoid (Flat and Depressed) Colorectal Neoplasms inAsymptomatic and Symptomatic Adults
Roy M. Soetikno; Tonya Kaltenbach; Robert V. Rouse; Walter Park;Anamika Maheshwari; Tohru Sato; Suzanne Matsui; Shai Friedland
JAMA. 2008; 299(9):1027-1035.
ClickHere For Abstract
Nonpolypoid Colorectal Neoplasia in the United States: TheParachute Is Open
David Lieberman
JAMA. 2008; 299(9):1068-1069.
ClickHere For Extract
Written by Anna Sophia McKenney
Copyright: Medical News Today
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