Giant Hyperplastic Polyp of the Colon Simulating Adenocarcinoma

Hyperplastic polyps of the colon have been previously reported as frequent incidental asymptomatic lesions limited to 1 cm. in size. To our knowledge, this is the first recorded case of a hyperplastic polyp of such magnitude as to cause obstractive symptoms and clinically simulate adenocarcinoma of the colon.     

The Relationship Between Distal and Proximal Colonic Neoplasia: A Meta-Analysis

OBJECTIVES  

To investigate the association between proximal colonic neoplasia and distal lesions as a function of the lesion type. The extent to which health, demographic, and study characteristics moderate this association was also examined.     

Impact of Adenoma Size in Distal Colon on Risk for Advanced Adenoma of the Proximal Colon

Adenomas of the rectosigmoid colon are considered markers of risk for advanced adenomas of the proximal colon. However, studies report a wide variation in risk. This study was designed to determine the risk for advanced adenomas in the proximal colon in patients from a large, homogeneous population with an advanced or nonadvanced adenoma of the distal colon. We designed a prospective study of 7157 patients who were evaluated for neoplasia by flexible sigmoidoscopy and, when adenomas were found, by colonoscopy. Adenomas were considered advanced if they were ≥10 mm in size or had villous or dysplastic features. Ninety-seven patients had an advanced adenoma of the distal colon (Group A) and were compared with 183 patients who had a nonadvanced adenoma (Group B). Seven patients (7.2%) in Group A had an advanced adenoma of the proximal colon, compared with four patients (2.2%) in Group B (P < 0.05, relative risk = 3.3). When patients with adenomas of the distal colon >5 mm (Group C) were compared to patients with adenomas ≤5 mm (Group D), the prevalence of advanced adenomas of the proximal colon remained at 7% (10/143) for Group C but fell to 0.73% (1/137) for Group D (P = 0.011, relative risk = 9.6). By expanding the criteria for risk from adenomas of the distal colon to include all adenomas >5 mm, the relative risk for advanced adenoma of the proximal colon was increased threefold.     

Ornithine Decarboxylase: An Unreliable Marker for the Identification of Population Groups at Risk for Colonic Neoplasia

Ornithine decarboxylase (ODC) is the first and rate-limiting enzyme in the polyamine biosynthetic pathway. Polyamines have been studied as potential markers of neoplastic diseases, including colonic cancer. Previous studies have pointed out the possible value of this enzyme as a biochemical marker of colonic neoplasia, we studied 100 patients undergoing diagnostic total colonoscopy. There were 40 normal controls and 20 patients in each of the following groups: 1) family members of patients diagnosed as having colonic tumors, 2) patients with adenomas, and 3) patients with colonic adenocarcinoma. Six forceps biopsies were obtained from the normal-appearing sigmoid mucosa for the analysis of ODC. No difference was found among the four groups studied. We therefore conclude that ODC is unreliable for clinical use as a biochemical marker for the identification of population groups at risk for colonic neoplasia.     

Sentinel Lymph Node Mapping for Adenocarcinoma of the Colon Does Not Improve Staging Accuracy

PURPOSE This study was designed to: determine the efficacy of sentinel lymph node mapping in patients with intraperitoneal colon cancer; and create an algorithm to predict potential survival benefit by using best-case estimates in favor of sentinel node mapping and lymph node ultraprocessing techniques. METHODS Forty-one patients with intraperitoneal colon cancer undergoing colectomy with curative intent were studied prospectively. After mobilization of the colon and mesentery, 1 to 2 ml of isosulfan blue dye was injected subserosally around the tumor. The first several nodes highlighted with blue dye were identified as sentinel nodes. Additional nodes were identified by the pathologist in routine fashion by manual dissection of the mesentery. All nodes were processed in routine fashion by bivalving and hematoxylin and eosin staining. To create an algorithm to predict potential survival benefit of sentinel node mapping and lymph node ultraprocessing techniques, assumptions were made using data from the literature. All bias was directed toward success of the techniques. RESULTS Three of 41 patients (7 percent) did not undergo injection of dye and were excluded from further analysis. Stage of disease in the remaining 38 patients was: I, n = 10 (26 percent); II, n = 15 (39 percent); III, n = 11 (29 percent); IV, n = 2 (5 percent). At least one sentinel node was identified in 30 of 38 patients (79 percent). The median number of sentinel nodes identified was two (range, 1–3). Median total nodal retrieval was 14 (range, 7–45). All nodes were negative in 26 of 38 patients (68 percent). Sentinel nodes and nonsentinel nodes were positive in 2 of 38 patients (5 percent). Sentinel nodes were the only positive nodes in 1 of 38 patients (3 percent). Sentinel nodes were negative and nonsentinel nodes were positive in 9 of 38 patients (24 percent). Thus, sentinel node mapping would have potentially benefited only 3 percent, and failed to accurately identify nodal metastases in 24 percent of the patients in our study. To create a survival benefit algorithm, we assumed the following: combined fraction of Stage I and II disease (0.5); fraction understaged by bivalving and hematoxylin and eosin staining that would have occult positive nodes by more sophisticated analysis (0.15); fraction of occult positive nodes detected by sentinel node mapping (0.9); and survival benefit from chemotherapy (0.33). Thus, the fraction of patients benefiting from sentinel lymph node mapping and lymph node ultraprocessing techniques would be 0.02 (2 percent). CONCLUSIONS Sentinel node mapping with isosulfan blue dye and routine processing of retrieved nodes does not improve staging accuracy in patients with intraperitoneal colon cancer. Even using best-case assumptions, the percentage of patients who would potentially benefit from sentinel lymph node mapping is small. Read at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004.     

Synchronous Cancers of the Colon and Rectum: Report of Eight Cases

This study reviews eight patients collected over a period of 3 yr with synchronous primary adenocarcinomas with special emphasis on presentation of illness, diagnosis, location of tumors, and their association with benign polyps. All of the synchronous carcinomas in this study were located in different surgical segments and all associated benign polyps were located in the same surgical segments. Workup included colonoscopy followed by completion of colon examination by barium enema. All patients underwent surgical resection of their tumors. It is therefore concluded that the incidence their tumors. It is therefore concluded that the incidence of synchronous tumors of the large colon is high enough to warrant total colon examination either by colonoscopy or barium enema.     

Proximal Location of Colon Cancer Is a Risk Factor for Development of Metachronous Colorectal Cancer: A Population-Based Study

PURPOSE This study was undertaken to assess the incidence of 1) metachronous colorectal cancer and 2) subsequent extracolonic cancers, in relation to the location (proximal or distal to the splenic flexure) of the first primary colorectal tumor.METHODS In this population-based study, a cancer registry database was used to identify patients diagnosed with colorectal adenocarcinoma between 1970 and 1999. Patients with familial adenomatous polyposis and those with hereditary nonpolyposis colorectal cancer syndrome were excluded from the study, as were patients with nonepithelial tumors. Location of the first tumor was established according to International Classification of Diseases-Oncology-02 classification. The registry covers a population of 500,000 residents.RESULTS A total of 5,006 patients had sporadic adenocarcinoma of the colon or rectum during this period of time, with 1,703 first primary tumors (34 percent) being located proximal to the splenic flexure. One hundred twenty occurrences of second primary colorectal cancer were observed in this population (2.39 percent). The risk for developing a second incidence of primary colorectal cancer was higher in patients whose initial tumor was located in the proximal colon (3.4 percent vs. 1.8 percent; odds ratio, 1.92; 95 percent confidence interval, 1.33–2.77; P < 0.001). The risk for each segment of the large bowel was as follows: cecum, 3.4 percent; right colon, 3 percent; transverse colon, 3.8 percent; left colon, 2.8 percent; sigmoid colon, 1.7 percent; and rectum, 1.8 percent. By contrast, the risk for developing a second, extracolonic tumor did not differ between patients with proximal and distal tumors (13.7 percent vs. 13.4 percent, P = 0.73).CONCLUSION Patients with a first tumor located within the proximal colon are at twice the risk for developing metachronous colorectal cancer. From an epidemiologic standpoint, these data are in accordance with 1) the increasing incidence and 2) the better prognosis of proximal colon cancer in various populations. Our results confirm that proximal colon cancer is a distinct entity, which justifies the reporting of cases of colon cancer according to their location proximal or distal to the splenic flexure.© The American Society of Colon and Rectal SurgeonsPublished online: 28 January 2005.Presented at the meeting of the American Gastroenterological Association, Orlando, Florida, May 17 to 22, 2003..     

Use of a Low Cut-Off Value for the Fecal Immunochemical Test Enables Better Detection of Proximal Neoplasia

Background

The advantage of the quantitative fecal immunochemical test (FIT) is the flexibility to set the positivity threshold. However, the diagnostic success of the FIT has not been compared for standard and low cut-off thresholds.

Aims

The purpose of this study was to compare the diagnostic success of FIT for standard and low cut-off thresholds.

Methods

In 2009 and 2010 a standard cut-off threshold (20 μg Hb/g feces) was used as positivity criterion for the FIT; in 2012 a low cut-off (10 μg Hb/g feces) was used. Diagnostic success was compared between the two groups.

Results

Of the total of 14,289 participants, 195 (1.4 %) had positive FIT results. Positivity of the FIT was significantly higher in the low cut-off group than in the standard cut-off group (1.8 vs. 1.0 %, p = 0.000). Although detection of advanced neoplasia lesions was comparable, proximal neoplasia was more frequently detected in the low cut-off group (33.3 vs. 20.9 %, p = 0.016). With the low cut-off threshold, 39 (0.7 %) participants were also classified as having positive results, and 18 (46.2 %) of these had colorectal neoplasias. The number of positive results from the FIT was increased by 54.9 %, and detection of advanced neoplasia was increased by 60 % with the low cut-off threshold compared with the standard cut-off.

Conclusions

A low cut-off threshold for the FIT resulted in better detection of proximal neoplasia in population-based screening. These results indicate the cut-off threshold for positive FIT should be properly chosen and adjusted in colorectal cancer screening.