Colorectal cancer in Asians: a demographic and anatomic survey in Malaysian patients undergoing colonoscopy

A 50-year review of colorectal cancer in African Americans: implications for prevention and treatment

BACKGROUND

African-Americans (AA) have the highest rate of colorectal cancer (CRC) incidence and mortality in the US. CRC in AA is more advanced and right-sided. Although screening has been shown to reduce mortality from CRC in the general US population, AA continue to experience a disproportionately higher CRC death compared to other ethnic groups. This study aimed at assessing the trend of CRC in AA, focusing on the changing pattern of in situ tumors in this ethnic group and how observed trends may guide current and future preventive and treatment strategies.

MATERIALS AND METHODS

All pathologic reports from 1959 to 2006 in Howard University Hospital (n = 150,000) were reviewed manually. The pathology reports showing colorectal cancer were carefully reviewed and selected by a GI pathologist. Intraepithelial or intramucosal carcinomas were diagnosed as in situ carcinoma. Reviewed pathological information were entered into Microsoft Excel and checked for duplication and missing data. Differences in situ and advanced cancer by sex, histology, location, and years of diagnosis were assessed by Chi-square test.

RESULTS

A total of 1,753 CRC cases were diagnosed in this period. About 56% of the cases were female and 51% of the tumors were left-sided. Mean (SD) age was 66 (13) years. The frequency of in situ tumor was 5.8% in this period. There was no statistically significant difference between in situ and advance tumor by age, sex, and tumor location. The rate of in situ tumor peaked in the 1990s at 8.5% (P = 0.0001). We observed a decade-to-decade increasing rate of right-sided tumors, which started at 36% in the period 1959-1970 and peaked in the period of 2001-2006 at 60% (P = 0.0001).

CONCLUSIONS

The recent increasing number of advanced and right-sided tumor in our study is concordant with SEER data and has great importance in developing CRC prevention and treatment strategies for AA population.

Changes on the disease pattern of primary colorectal cancers in Southern China: a retrospective study of 20 years

PURPOSE

Some changes on the disease pattern of colorectal cancer (CRC) have occurred in some Asian countries recently. However, nothing is known about it in China lately. The present study is to determine whether there are any changes on the disease pattern of CRC in Southern China.

PATIENTS AND METHODS

Data were collected from all consecutive patients accepting colonoscopy in our endoscopy center during the last 20 years. The sociodemographic data, clinical presentations, endoscopic descriptions, and histological subtypes of patients confirmed as CRC by pathology were analyzed retrospectively.

RESULTS

A total of 37,578 patients accepted colonoscopy from 1987 to 2006, in which 2,876 patients were diagnosed as CRC. The median age of patients in the 2nd decade (1997-2006; 62 years) was getting older than the 1st decade (1987-1996; 58 years; P = 0.043). Hematochezia was the most frequent symptom (55.8%), while rectum was the most common site distribution of CRC (51.0%). The incidence of right-sided colonic cancers in the 2nd decade (21.0%) was higher than the 1st decade (17.3%; P = 0.0314). Histologically, adenocarcinoma was the most common (92.4%), of which moderately differentiated tumors were more frequent (67.7%). CRCs with high-grade malignancy were more likely to occur in the 1st decade (P < 0.0001).

CONCLUSIONS

Rectum remains the most common site of CRC in southern China. But a rightward shift in the site distribution has occurred and patients are getting older. Tumors with high-grade malignancy have the tendency to decrease.

Predictors of gastrointestinal lesions on endoscopy in iron deficiency anemia without gastrointestinal symptoms

BACKGROUND

Iron deficiency anaemia (IDA) due to occult gastrointestinal (GI) blood loss usually remains unnoticed until patient become symptomatic. There is sparse data in IDA patients without gastrointestinal symptoms. This study was designed to find out the frequency and predictors of endoscopic lesions in IDA without gastrointestinal symptoms. Cross-sectional study performed on a convenience sample of consecutive subjects.

METHODS

Ninety five consecutive patients with laboratory based diagnosis of IDA having no gastrointestinal symptoms were interviewed and their clinical and biochemical variables were recorded. All the study patients underwent esophago-gastroduodenoscopy (EGD) and colonoscopy. Endoscopic findings were documented as presence/absence of bleeding related lesion and presence/absence of cause of IDA. Multiple logistic regressions were performed to identify variables significantly related to outcome variables.

RESULTS

Possible cause of anaemia was found in 71% and bleeding related lesions were found in 53% of patients. Upper gastrointestinal tract lesions were found in 41% of patients with bleeding related lesions. On multivariable logistic regression; advancing age, low mean corpuscular volume (MCV Collapse

Key Words Collapse

MESH Headings

• Adult
• Age Factors
• Aged
• Anemia, Iron-Deficiency/etiology
• Cross-Sectional Studies
• Endoscopy, Digestive System
• Erythrocyte Indices
• Female
• Gastrointestinal Diseases/complications
• Gastrointestinal Diseases/diagnosis
• Gastrointestinal Hemorrhage/complications
• Gastrointestinal Hemorrhage/diagnosis
• Humans
• Logistic Models
• Male
• Middle Aged
• Occult Blood
• Predictive Value of Tests

Collapse

Grants Collapse

Affiliation(s)

Shahid Majid Section of Gastroenterology, Department of Medicine, Aga Khan University Hospital, Karachi, Pakistan
Mohammad Salih Section of Gastroenterology, Department of Medicine, Aga Khan University Hospital, Karachi, Pakistan
Rozina Wasaya Section of Gastroenterology, Department of Medicine, Aga Khan University Hospital, Karachi, Pakistan
Wasim Jafri Section of Gastroenterology, Department of Medicine, Aga Khan University Hospital, Karachi, Pakistan

Collapse

Clinical and pathologic outcomes of colorectal cancer in a multi-ethnic population

BACKGROUND & AIMS

The influence of birthplace on the clinical and pathologic outcomes of colorectal cancer (CRC) in Australia is unknown. Addressing inequalities in health care provision in immigrant groups may improve the overall quality of CRC care.

METHODS

The South Western Sydney Colorectal Tumour Group registry prospectively collects data on new patients with CRC from a population of 800,000. Survival data were cross-linked with the New South Wales population death registry.

RESULTS

From 1997 to 2004 there were 1496 patients (55% males) who were recruited and grouped according to country of birth: Australia, 64%; Southern Europe, 19%; Asia, 12%; and the Middle East, 5%. Significant heterogeneity in CRC characteristics was found, especially in Asians. Compared with Australians, Asians were diagnosed at a younger age (median age, 64 vs 70 y; P < .001, 25.6% were younger than 50 years vs 9.5%; P < .001), had fewer poorly differentiated cancers (8.9% vs 17.7%; P = .004), and fewer metastatic cancers (12.1% vs 21.0%; P = .001). Being Asian-born was associated with improved overall survival independent of age, emergency surgery, grade, and stage (hazard ratio, 0.66; 95% confidence interval, 0.47-0.93; P = 0.02). CRC screening was especially low among Asian- and Middle Eastern-born patients. Complications and treatment were not affected by birthplace, indicating no differences in the provision or acceptance of care based on birthplace.

CONCLUSIONS

Despite an equitable distribution of resources, we found significant heterogeneity in presentations and outcomes according to birthplace, with improved survival in Asian-born patients. The lower rates of screen-detected CRC in Asian- and Middle Eastern-born patients and their younger ages at diagnosis indicate that targeted screening strategies may need to be implemented.

The efficacy of intravenous contrast-enhanced 16-raw multidetector CT colonography for detecting patients with colorectal polyps in an asymptomatic population in Korea

PURPOSE

The purpose of this study is to compare the sensitivity of computed tomography (CT) colonography (CTC) with that of colonoscopy for detecting patients with colorectal polyps in an asymptomatic screening population in Korea, thus to evaluate a possibility, whether CTC could be used as a screening tool for colorectal polyps.

METHODS

A total of 241 asymptomatic adults underwent intravenous contrast-enhanced CTC and colonoscopy successively on the same day. Bowel preparation was performed by 4 L of polyethylene glycol (n=172) or 90 mL of sodium phosphate (n=69). The CTC findings were released to the colonoscopists after the first examination of each segment, a procedure known as segmental unblinded colonoscopy, and were used as the reference standard. The diagnostic performance of CTC for colorectal polyps was calculated.

RESULTS

The per-patient sensitivities of CTC were 68.5% (37/54) and 86.7% (13/15) for polyp > or = 6 and > or = 10 mm, inferior to those of colonoscopy, 92.6% (50/54) and 100% (15/15), respectively. The per-polyp sensitivities of CTC were 60.4% (61/101) and 72.7% (16/22) for polyp > or = 6 and > or = 10 mm, respectively. The low sensitivity of CTC was related with flat morphology. CTC detected only 37.5% (9/24) of flat polyps > or = 6 mm. Bowel preparation by sodium phosphate further decreased the positive predictive value and specificity than by polyethylene glycol.

CONCLUSIONS

Screening by CTC with asymptomatic population was not promising in Korea despite using advanced CT technology (16-row detector). Bowel preparation was one of the key determinants of the specificity of CTC.

Clinical predictors of colorectal polyps and carcinoma in a low prevalence region: Results of a colonoscopy based study

AIM: To estimate the prevalence of colorectal cancer (CRC) in patients with long lasting colonic symptoms undergoing total colonoscopy; and to establish clinical features predicting its occurrence.

METHODS: This prospective study was carried out in Imam Hospital, Tabriz University of medical sciences, Iran. Continuous patients with long lasting lower gastrointestinal tract symptoms who had the criteria of a colonoscopy were included. The endoscopist visualized the caecum documented by a photo and/or a specimen from terminal ileum.

RESULTS: Four hundred and eighty consecutive symptomatic patients [mean age (SD): 42.73 (16.21)] were included. The prevalence of colorectal neoplasia was 15.3% (34 subjects) and 37.7% (181 subjects) had a completely normal colon. Adenomatous polyps were detected in 56 (11.7%) patients, in 12.3% of men and 10.9% of women. The mean age of the patients with a polyp was significantly higher than the others (49.53 ± 14.16 vs 41.85 ± 16.26, P = 0.001). Most of the adenomatous polyps were left sided and tubular; only 22.5% of polyps were more than 10 mm. Cancer was detected in 16 (3.6%) of our study population, which was mostly right sided (57.2%). The mean age of patients with cancer was significantly higher than the others (60.25 ± 8.26 vs 42.13 ± 16.08, P < 0.005) and higher than patients with polyps [60.25 (8.26) vs 49.53 (1.91) (P < 0.0005)]. None of the symptoms (diarrhea, abdominal pain, rectal bleeding, constipation, altering diarrhea and constipation, history of cancer, known irritable bowel disease, history of polyp and fissure or family history of cancer) were predictors for cancer or polyps, but the age of the patient and unexplained anemia independently predicted cancer.

CONCLUSION: Less advanced patterns and smaller sizes of adenomas in Iran is compatible with other data from Asia and the Middle East, but in contrast to western countries. Prevalence of colonic neoplasia in our community seems to be lower than that in western population. Colonic symptoms are not predictors for polyps or cancer but unexplained anemia and elder age can predict CRC.

Q&A on diagnosis, screening and follow-up of colorectal neoplasia

The impressive and brisk evolution of medical science prevents many physicians from a thorough update on all the research fields. Colorectal cancer diagnosis, screening and follow-up is well known to require a multi-disciplinary approach, as it is faced by several specialties such as primary care physicians, gastroenterologists, non-gastroenterologist internists, radiologists and surgeons. To address this issue in a mutual perspective, we focused on the main points of the epidemiology, diagnosis, screening and follow-up of colorectal neoplasia by using a simple "Question & Answers" structure.

Genetic alterations of APC, K-ras, p53, MSI, and MAGE in Korean colorectal cancer patients

BACKGROUND AND AIM

Colorectal cancer (CRC) is one of the most rapidly increasing cancers in Korea, but no comprehensive analysis has been performed to speculate the genetic basis of CRC development. We investigated the presence of adenomatous polyposis coli gene (APC), Kirsten-ras (K-ras), p53, microsatellite instability (MSI), and melanoma antigen gene (MAGE) alterations in CRC and correlated the results obtained with clinical data.

MATERIALS AND METHODS

We collected 78 cancer tissues from CRC patients. Genetic analyses were performed on APC, K-ras, p53, and MSI (BAT 25 and BAT 26), and in addition, MAGE expression was tested by reverse transcription polymerase chain reaction. Correlations between genetic markers and clinical factors were analyzed after reviewing medical records.

RESULT

The positive rates for alterations of APC, K-ras, p53, MSI, and MAGE in 78 tissue samples were 33.3, 29.5, 34.6, 9.0, and 68.4%, respectively. Mutations were frequently detected in codons 1291 and 1450 of APC, in codon 12 of K-ras and in codons 248, 282, and 176 of p53. APC mutations were frequently noted in early-stage cancer, whereas MSI was observed in right-sided and multiple cancers. No associations were found between the presence of alterations in APC, K-ras, p53, MSI, and MAGE.

INTERPRETATION

In Koreans, positive rates of alterations in APC and p53 were slightly lower than those of APC and p53 in Caucasians, and the genetic alterations including MAGE expression are involved in 92.1% of CRCs. The lack of multiple mutations and of a relation between mutation rates and clinical stage suggest that genetic alterations might have independent influences on CRC development in Koreans.

Changing trends in gastrointestinal disease in the Asia-Pacific region

The new millennium has seen distinct changes in the pattern of gastrointestinal disease in the Asia-Pacific region. These changes are important as more than half of the world's population come from the region and therefore impact significantly on the global disease burden. The highest incidence of gastric cancer (GCA) has been reported from Asia and GCA remains a very important cancer. However time-trend studies have shown a decrease in GCA incidence in several countries in Asia. A rise in cardio-esophageal cancers as seen in the West has not been reported. On the other hand, colorectal cancer has been steadily increasing in Asia with age-standardized incidence rates of some countries approaching that of the West. The pattern of acid-related diseases has also changed. Gastroesophageal reflux disease is a fast emerging disease with an increasing prevalence of reflux esophagitis and reflux symptoms. The prevalence of peptic ulcer disease has at the same time declined in step with a decrease in H. pylori infection. Many of the changes taking place mirror the Western experience of several decades ago. Astute observation of the epidemiology of emerging diseases combined with good scientific work will allow a clearer understanding of the key processes underlying these changes. With rapid modernization, lifestyle changes have been blamed for an increase in several diseases including gastroesophageal reflux disease, nonalcoholic fatty liver disease and colorectal cancer. A worrying trend has been the increase in obesity among Asians, which has been associated with an increase in metabolic diseases and various gastrointestinal cancers. Conversely, an improvement in living conditions has been closely linked to the decrease in GCA and H. pylori prevalence.

Detection and treatment of synchronous lesions in colorectal cancer: The clinical implication of perioperative colonoscopy

AIM: To evaluate the clinical significance of pre- and intra-operative colonoscopy for the detection of synchronous lesions in colon cancer.

METHODS: Two hundred and sixty-five pre-operative and 51 intra-operative colonoscopic evaluations were performed in 316 colorectal cancer patients who underwent curative resection from January 2001 to June 2006. The incidence and characteristics of synchronous lesions and their influence on surgery were evaluated.

RESULTS: Two hundred and eighty-two synchronous lesions were detected in 124 (39.2%) of 316 patients including all lesions regardless of their histologic type. True adenomatous polyps were found in 91 (28.8%) of 316 patients, and 17 (5.4% of all patients) patients had synchronous colon cancers. The preoperative identification of synchronous lesions altered the planned surgery in 37 (14.0%) of 265 patients. In 18 patients among the surgically removed cases, the lesions were removed by extending the resection range. Further segmental resection or polypectomy through enterotomy was necessary in 19 patients. Nineteen (37.2%) of 51 intraoperative colonoscopy cases had synchronous lesions. Additional surgical procedures including segmental bowel resection and polypectomy with enterotomy were necessary in 7 (13.7%) of 51 intraoperative colonoscopy cases to remove the lesions.

CONCLUSION: Synchronous colorectal polyps or cancer are frequent and their preoperative detection is important for optimal surgical planning and treatment. Intraoperative colonoscopy is a useful option in cases where a preoperative colonoscopy is not feasible.

Colonoscopy in elderly Asians: a prospective evaluation in routine clinical practice

OBJECTIVE

Colonoscopy is believed to be more complicated in elderly patients in Western countries. It is uncertain if the situation holds true among Asians. This study is to determine differences in colonoscopy performance and sedation complications between patients aged<65 years and those>or=65 years of age in an Asian population.

METHODS

A prospective, cross-sectional study of adults attending outpatient colonoscopy at a tertiary institution. Clinical and endoscopic data were obtained from all consenting adults.

RESULTS

Two hundred and one patients (70 elderly and 131 aged<65 years) were enrolled. Compared to the patients aged<65 years, the elderly patients had similar levels of good (42.9%vs 45.8%), satisfactory (42.9%vs 33.6%) and poor (14.3%vs 20.6%) bowel preparations (P=NS). Cecal intubation was achieved in 60 (85.7%) of the elderly patients and 116 (88.5%) of the younger adults (P=NS). The differences in mean total colonoscopy duration was not significant (30+/-13 vs 27+/-11 min). Although the elderly patients received lower mean sedation doses of midazolam (4.7 vs 5.1 mg) and pethidine (37.8 vs 46.4 mg) compared to the younger adults, the hypotension rates were significantly higher in the elderly patients (7.1%vs 0.8%, P=0.01). The elderly patients had in additional one or more co-morbid illnesses (P=0.001), with significantly higher rates of diabetes (P=0.004), ischemic heart disease (P=0.03), hypertension (P=0.001) and stroke disease (P=0.004).

CONCLUSION

Colonoscopy performance in elderly Asians is similar to that in younger adults. However, the conscious sedation of these patients results in a higher rate of cardio-vascular complications.

Screening for colorectal cancer in average-risk Chinese population using a mixed strategy with sigmoidoscopy and colonoscopy

PURPOSE

The Chinese population has been shown to have more distal colonic neoplasm and a higher sensitivity of sigmoidoscopic screening strategy for detecting advanced neoplasm compared with Western populations. This study was designed to evaluate the efficacy of the mixed screening strategy with sigmoidoscopy and colonoscopy in the average-risk Chinese population.

METHODS

Consecutive average-risk adults aged >/=50 years who underwent colonoscopy as part of a health checkup were enrolled. Data were analyzed in a hypothetical graded screening strategy using colonoscopy on patients older than a certain cutoff age or those with distal sentinel polyps. The sensitivity in detecting advanced colonic neoplasm and advanced proximal neoplasm as well as the number of colonoscopies reduced were assessed.

RESULTS

Of the 2,106 persons eligible for analysis, 1,193 (56.6 percent) were males and 913 (43.4 percent) were females. If the cutoff ages were 55, 60, and 65 years, and adenoma detected in the distal colon was the indication for subsequent colonoscopy, the detection rate for 1) advanced colonic neoplasm in the entire colon would be 94, 93.1, and 83.6 percent, respectively, and 2) advanced proximal neoplasm would be 84.8, 82.6, and 58.7 percent, respectively. The number of colonoscopic procedures could be reduced by 28, 48, and 65 percent if the cutoff ages were 55, 60, and 65 years, respectively.

CONCLUSIONS

The mixed screening strategy using a cutoff age at 60 years and distal adenoma as the sentinel lesion is an effective screening program in the average-risk Chinese population.

No difference in the occurrence of mismatch repair defects and APC and CTNNB1 genes mutation in a multi-racial colorectal carcinoma patient cohort

BACKGROUND AND AIMS

Colorectal cancers of different subtypes involve different pathogenic pathways like the Wnt and the mutator pathways. In this study, we screened 73 colorectal cancer cases from a multi-racial group for genetic and expression profile defects with the aim of correlating these with patients' clinicopathological characteristics.

METHODS

Mutation screening of the entire coding region of APC and exon 3 of CTNNB1, loss of heterozygosity (LOH) of APC, and microsatellite instability (MSI) status were assessed for 44 patients with available paired frozen normal and tumour tissues. In addition, 29 cases with available paraffin embedded tumour blocks were screened for mutation in exon 3 of CTNNB1, the APC mutation cluster region (codon 1286-1513), and hMLH1, hMSH2, hMSH6 protein expressions by immunohistochemistry method.

RESULTS

In our study, 15/73 cases showed APC mutations (20.5%), 1/73 cases had CTNNB1 mutation (1.4%), 5/32 cases had APC LOH (15.6%), and 16/70 (22.9%) cases revealed at least some form of mismatch repair (MMR) defect. Tumour grade (poor differentiation) was found to correlate significantly with right-sided tumour and mucinous histology (p = 0.01879 and 0.00320, respectively). Patients of younger age (below 45 years) more often had tumours of mucinous histology (p = 0.00014), while patients of older age (above 75 years) more often had tumours on the right side of the colon (p = 0.02448). Tumours of the mucinous histology subtype often had MMR defects (p = 0.02686). There was no difference in the occurrence of APC and CTNNB1 mutations and MMR defects found within our multi-racial colorectal cancer patient cohort.

CONCLUSION

Our findings support the notion that racial factor may not be related to the occurrence of MMR defects and APC and CTNNB1 mutations in our multi-racial patient cohort.

Differential gene expression between flat adenoma and normal mucosa in the colon in a microarray analysis

BACKGROUND

Flat adenomas in the colon are associated with a relatively higher potential for malignancy. Distinct genes may be involved in the development of flat adenoma. The aim of this study was to profile gene expression changes in flat adenomas in the colon.

METHODS

A genomewide expression analysis was carried out by using flat adenoma and adjacent normal mucosa in the colon to detect differences in gene expression. Because the right and left colon have different embryonic origins, each sample was classified according to its location, and the gene expression levels between flat adenoma and adjacent normal mucosa were also compared among samples derived from the right or left colon.

RESULTS

A total of 180 genes were differentially expressed between flat adenoma and normal mucosa in the colon, including matrix metalloproteinase 7 (MMP7), cadherin 3 (CDH3), S100P, and dual oxidase 2 (DUOX2). In addition, a total of 89 and 49 genes were differentially expressed between flat adenoma and normal mucosa among the samples from the right and left colon, respectively. Subsequent quantitative real-time reverse transcriptase-polymerase chain reaction supported the reliability of the expression analysis. Immunohistochemical analysis confirmed differential CDH3 and MMP7 protein expression.

CONCLUSIONS

This is the first report characterizing the genes differentially expressed in flat adenomas using a microarray analysis. Considerable differences in the gene expression profiles of flat adenomas also exist between the right and left colon. These data should lead to new insights into the pathogenesis of flat adenomas in the colon as well as to new therapeutic strategies.