Incidence pattern of colorectal cancer in Korea by subsite of origin

Laparoscopic surgery for rectal cancer, specimen extraction: transanal or transabdominal?

BACKGROUND

Comparison of natural orifice specimen extraction (NOSE) and transabdominal specimen extraction (TASE) in colorectal surgery remains controversial. Herein, we aimed to perform a retrospective analysis on surgical outcomes of NOSE and TASE at three hospitals in east of Iran.

METHOD

Consecutive locally advanced rectal adenocarcinoma patients who underwent laparoscopic surgery using either NOSE or TASE from 2011 to 2017 were recruited. These patients were followed-up till 2020. Data, including postoperative complications, long-term overall and recurrence-free survival were analyzed retrospectively.

RESULTS

239 eligible patients were included in this study. 169 (70.71%) patients underwent NOSE, and 70 (29.29%) patients underwent TASE. Although this study has achieved similar outcomes in terms of overall and recurrence-free survival, metastasis, circumferential margin involvement as well as complications of intra-operative bleeding, obstruction, anastomosis-fail, rectovaginal-fistula in women and pelvic collection/abscess in both groups, we observed higher rates of locoregional recurrence, incontinency, stenosis and the close distal margins involvement in NOSE group and also obstructed defecation syndrome in TASE cases.

CONCLUSION

According to our findings, NOSE laparoscopic surgery showed significantly higher incontinency, impotency, stenosis and involvement of the close distal margins rates. Nevertheless, considering the similarity of long-term overall and recurrence-free survival, metastasis, circumferential margin involvement, NOSE procedure is still could be considered as a second choice for lower rectal adenocarcinoma patients.

Changing Colorectal Cancer Trends in Asians: Epidemiology and Risk Factors

Once an infrequent disease in parts of Asia, the rate of colorectal cancer in recent decades appears to be steadily increasing. Colorectal cancer represents one of the most important causes of cancer mortality worldwide, including in many regions in Asia. Rapid changes in socioeconomic and lifestyle habits have been attributed to the notable increase in the incidence of colorectal cancers in many Asian countries. Through published data from the International Agency for Cancer Research (IARC), we utilized available continuous data to determine which Asian nations had a rise in colorectal cancer rates. We found that East and South East Asian countries had a significant rise in colorectal cancer rates. Subsequently, we summarized here the known genetics and environmental risk factors for colorectal cancer among populations in this region as well as approaches to screening and early detection that have been considered across various countries in the region.

Metabolic syndrome and colorectal adenoma risk: A systematic review and meta‑analysis

OBJECTIVE

Whether metabolic syndrome is a risk factor of colorectal adenoma has spurred debate. We systematically meta-analyzed all clinical studies associated with metabolic syndrome (MetS)/metabolic components and colorectal adenoma risk and quantified the dose-response association between them, aiming to provide more clues for better decision-making.

METHODS

We searched PubMed, EMBASE, and Cochrane Library through June 2020 for clinical studies of MetS and colorectal adenoma risk. RevMan 5.3 software and STATA 12.0 software were employed for meta-analysis.

RESULTS

Seventeen studies representing 44,336 participants were eligible for analysis. The overall meta-analysis showed that MetS patients had increased risk of colorectal adenoma (OR: 1.39, 95% CI 1.24-1.57; P < 0.05). Dose-response analysis presented that every increased number of Mets components was associated with a 8% increment of colorectal adenoma risk(OR: 1.08; 95% CI: 1.04-1.11). Subgroup analysis by age revealed a higher colorectal adenoma risk in MetS patients 50 years or older (OR 1.46; 95% CI 1.21-1.76; P < 0.0001), rather than MetS patients younger than 50 years old (OR 1.23; 95% CI 0.95-1.59; P = 0.11).When stratified by sex, the analysis revealed a higher risk of colorectal adenoma in male MetS patients (OR 1.32; 95% CI 1.15-1.53; P = 0.0001), rather than females (OR 1.65; 95% CI 0.90-3.02; P = 0.10). The analysis split by adenoma location showed that the right colon (OR 1.35; 95% CI 1.04-1.75; P = 0.03), instead of the left colon (OR 1.16; 95% CI 0.84-1.59; P = 0.37) or rectum(OR 1.26; 95% CI 0.89-1.78; P = 0.20), was the predilection site associated with increased colorectal adenoma risk in MetS patients.

CONCLUSIONS

Overall, our meta-analysis showed that MetS was associated with a higher risk of colorectal adenoma. MetS patients, especially old (≥50 years) male patients, should be a risk population for colorectal adenoma screening so that they can benefit from behavioural interventions that can help prevent the development of colorectal cancer.

Classifying interval cancers as false negatives or newly occurring in fecal immunochemical testing

OBJECTIVE

To classify interval colorectal cancers as false negatives or newly occurring cases in a biennial Fecal immunochemical test (FIT) screening program and by various interscreening intervals.

SETTING

Data from the Taiwanese biennial colorectal cancer screening program involving FIT from 2004 to 2014 were used to estimate the incidence rate of asymptomatic colorectal cancer and the rate of its subsequent progression to clinical mode.

METHODS

The sensitivity of detecting asymptomatic colorectal cancers excluding newly developed colorectal cancers was compared to the conventional estimate of sensitivity, the complementary FIT interval cancer rate as a percentage of the expected incidence rate ((1-I/E)%). The relative contribution of newly developed or false-negative cases to FIT interval colorectal cancers was estimated by age and interscreening intervals.

RESULTS

The Taiwanese biennial fecal immunochemical test screening program had a conventional sensitivity estimate of 70.2%. After newly developed colorectal cancers were separated from FIT interval cancers, the ability to detect asymptomatic colorectal cancers increased to 75.5%. FIT interval colorectal cancers from the biennial program mainly resulted from newly developed colorectal cancers (68.8%). The corresponding figures decreased to 61.1% for the annual program but increased to 74.7% for the triennial program. The preponderance of newly developed colorectal cancers among FIT interval cancers was more prominent in screenees aged 50-59  than in those aged 60-69.

CONCLUSIONS

Newly developed colorectal cancers showed a predominance among the FIT interval colorectal cancers in particular in the younger population screened. It is desirable to identify high-risk individuals to offer them a short interscreening interval or advanced detection methods to reduce their odds of developing interval cancer.

Emerging Gastrointestinal and Liver Diseases in Asia Pacific: Implications to Health Care in the Region (World Gastroenterology Organization: Asian Pacific Association of Gastroenterology Distinguished Global Lecture 2015)

Colorectal cancer (CRC), gastroesophageal reflux disease (GERD), inflammatory bowel disease (IBD), and nonalcoholic fatty liver disease are considered important emerging diseases in the Asia Pacific (AP) region. The incidence rate of CRC is the highest among gastrointestinal cancers in the region surpassing that of gastric cancer. However, population CRC screening is limited by availability of adequate health resources and financing. GERD is a highly prevalent disease in AP with the prevalence of GERD symptoms and reflux esophagitis reported to be increasing. The usage of proton pump inhibitors has also been reported to be high. The incidence and prevalence of IBD is not as high as in the west but is now an increasingly recognizable disease in the AP region. Being a complicated disease, IBD will pose a huge financial burden with the increasing use of expensive biological drugs. In tandem with the exponential increase in obesity and diabetes mellitus in AP, nonalcoholic fatty liver disease will become the most important liver disease in the region in the coming years. These emerging diseases reflect the continued fast-paced socioeconomic development in the region with marked lifestyle changes and increasing affluence.

Identifying the optimal strategy for screening of advanced colorectal neoplasia

BACKGROUND AND AIM

To guide selection of optimal screening strategies for advanced colorectal neoplasia (ACRN), we evaluated the screening performances of sigmoidoscopy, fecal immunochemical test (FIT), and the Asia-Pacific Colorectal Screening (APCS) system, as well as combinations of these techniques.

METHODS

We reviewed the records of participants who had undergone a colonoscopy and FIT as part of a comprehensive health-screening program. Results of sigmoidoscopy were estimated from lesions under colonoscopic examination. The screening strategies were classified as sigmoidoscopy-based, FIT-based, and APCS-based. The sensitivity and reduction of number needed to colonoscope (NNScope) of each screening strategy were assessed.

RESULTS

Of 23 023 participants, 398 (1.7%) had ACRN. To predict the presence of ACRN, sigmoidoscopy was the most effective method (odds ratio [OR]: 22.96, 95% confidence interval [CI]: 18.26-29.07), followed by FIT (OR: 7.18, 95% CI: 5.28-9.68) and APCS (high risk [≥4] OR: 2.59, 95% CI: 1.87-3.58; moderate risk [2-3] OR: 1.66, 95% CI: 1.28-2.17). Regarding sigmoidoscopy-based strategies, "sigmoidoscopy positive alone" and "sigmoidoscopy positive or APCS ≥4" were optimal strategies (reduction of NNScope: 79-86%; sensitivity: 73-78%). In the case of FIT-based strategies, "FIT positive or APCS ≥4" was the optimal strategy (reduction of NNScope: 72%; sensitivity: 37%). With regard to the APCS system only, "APCS ≥2" and "APCS ≥4" were recommended as sensitivity-preferred and reduction in NNScope-preferred strategies, respectively.

CONCLUSIONS

The performance in ACRN prediction differs among screening methods (sigmoidoscopy, FIT, and APCS). Among the various single or combined screening strategies, several specific strategies can be chosen depending on medical resources, financial budgets, and screenee preference.

Colorectal cancer incidence in 5 Asian countries by subsite: An analysis of Cancer Incidence in Five Continents (1998-2007)

Colorectal cancer is the fourth most common cancer in Asia. However, the trends in colorectal cancer incidence by subsite have not been analyzed across Asian countries. We used the most recent, high quality data from 6 cancer registries for two 5-year periods, 1998-2002 and 2003-2007, from Cancer Incidence in Five Continents to estimate colorectal cancer incidence by subsite in 5 Asian countries. Cases with overlapping lesions or otherwise unspecified colon cancer were re-distributed as proximal or distal colon cancer. Age-standardized incidence rates (ASRs) per 100,000 population and incidence rate ratios from 1998 to 2002 to 2003-2007 were calculated for each subsite. For 2003-2007, men in Miyagi, Japan, had the highest ASR for cancer in the proximal colon, distal colon and rectum. Men of Jewish ancestry in Israel had a high ASR for proximal and distal colon cancer, but the lowest ASR for rectal cancer. The proportion of rectal cancer was highest among Korean men (51.39%) and lowest among Israeli women (26.6%). From 1998-2002 to 2003-2007, rectal cancer incidence did not significantly change in most registries, except for men in Miyagi, Japan, and both sexes in Korea. However, during the same period cancer incidence in the proximal and distal colon increased in most registries. In conclusion, there was substantial variation in subsite distributions of colorectal cancer in Asian registries and increases in overall incidence of colorectal cancer could be attributed to increases in colon cancer.

Study of Clinicopathological Profile of Sporadic Cases of Colorectal Cancer

Objectives

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the world. This study was carried out to see the epidemiological and clinicopathological profile of sporadic cases of CRC in Bangladesh.

Materials and methods

The patients diagnosed to have colorectal carcinoma in two private medical centers of Bangladesh from January 2012 to December 2014 were enrolled in this study. Demographic data, clinical presentations, site of lesions, and histological types were analyzed.

Results

Total 158 patients were included in this study. The mean age was 50.77 years and male to female ratio was 1.55:1. Rectal bleeding was the commonest symptom irrespective of age and sex followed by abdominal pain (33, 20.9%), weight loss (29, 18.3%), abdominal mass (26, 16.4%), and altered bowel habit (22, 13.9%). Common histological type was adenocarcinoma (156, 98.7%).

Conclusion

Colorectal cancer commonly affects males >40 years of age. Most common site of involvement is rectum, which is followed by left colon.

How to cite this article

Saha M, Shil BC, Saha SK, Banik RK, Perveen I, Chowdhury MKS, Nazmul Islam ASM, Saifullah ANM. Study of Clinicopathological Profile of Sporadic Cases of Colorectal Cancer. Euroasian J Hepato-Gastroenterol 2016;6(2):134-136.

Frequent BRAF mutation in early-onset colorectal cancer in Taiwan: association with distinct clinicopathological and molecular features and poor clinical outcome

BACKGROUND

Occurrence of early-onset colorectal cancer (EOCRC) under the age of 30 is very rare and the molecular characteristics are poorly understood. A low BRAF mutation rate has been noted in several studies of EOCRC from Western countries.

AIMS

To determine the clinicopathological and molecular features of EOCRCs in Taiwan.

METHODS

KRAS/BRAF gene mutation, mismatch repair protein immunohistochemistry, microsatellite instability and CpG island methylation phenotype analyses were examined to determine the molecular characteristics of EOCRC.

RESULTS

Sixty-six patients with EOCRC at our hospital between 2000 and 2012 were studied. BRAF mutation was detected in 11 of the 59 tumours analysed (19%) and the rate was significantly higher than the overall BRAF mutation rate of colorectal cancer in patients older than 30 years (p<0.001). Clinically, 9 of 11 patients with BRAF-mutated tumours presented with advanced-stage diseases and they presented significantly more frequently with stage IV disease than those with BRAF wild-type tumours (p=0.042). Histologically, BRAF mutation was associated with a poorly differentiated histology, a serrated precursor polyp and focal signet ring cell differentiation (p=0.042, 0.008 and 0.008, respectively). None of the BRAF-mutated tumours was mismatch repair protein-deficient and/or microsatellite instability-high. Overall survival of patients with BRAF-mutated tumours was significantly worse than that of patients with BRAF wild-type tumours, despite adjustment for the disease stages and tumour differentiation.

CONCLUSIONS

BRAF mutation was frequent in EOCRCs in Taiwan and was associated with distinct clinicopathological and molecular features.

Observations on the epidemiology of gastrointestinal and liver cancers in the Asia-Pacific region

Gastric cancer (GC) has long been thought to be an Asian type of cancer that is broadly associated with poverty, whereas colorectal cancer (CRC) has been thought to be a Western type of cancer associated with affluence. The incidence of GC has declined dramatically in the West but has a very high incidence in East Asia. The age-standardized incidence rates (ASR) have also declined. The decrease in the incidence of GC is associated with the decrease in the prevalence of Helicobacter pylori (H. pylori) infection worldwide. The discrepancy between a high H. pylori infection rate and a low GC incidence is seen chiefly among southern Asians of Indian origin and has been aptly termed the "Indian enigma". CRC is a new emerging cancer in this region. Some of the highest CRC ASR have been reported from Asian countries, in many of which it has now surpassed that of GC. Liver cancer is also an important cancer in the Asia-Pacific region. The highest ASR worldwide is reported from the Asian countries of Mongolia, Korea and Japan. The predominant underlying etiology across the region has been hepatitis B virus infection, except in Japan, where hepatitis C is an important cause of hepatocellular carcinoma (HCC). With mass vaccination of hepatitis B at birth and improved public health measures in many countries, hepatitis B and C are set to decline with time. However, the exponential increase in obesity and consequent non-alcoholic fatty liver disease portends a future epidemic of fatty liver-related HCC.

Hospital-based colorectal cancer survival trend of different tumor locations from 1960s to 2000s

Background

Our aim is to explore the trend of association between the survival rates of colorectal cancer (CRC) and the different clinical characteristics in patients registered from 1960s to 2000s. We hypothesized that the survival rate of CRC increases over time and varies according to anatomic subsites.

Methods

Information from a total of 4558 stage T_(1-4)N_(1-2)M₀ CRC patients registered from 1960s to 2008 were analyzed. The association of CRC overall survival with age, gender, tumor locations, time, histopathology types, pathology grades, no. of examined lymph nodes, the T stage, and the N stage was analyzed. The assessment of the influence of prognostic factors on patient survival was performed using Cox’s proportional hazard regression models.

Results

From 1960 to 2008, the studied CRC patients included 2625 (57.6%) and 1933 (42.4%) males and females, respectively. These included 1896 (41.6%) colon cancers, and 2662 (58.4%) rectum cancers. The 5-year survival rate was 49%, 58%, 58%, 70%, and 77% for the time duration of 1960s, 1970s, 1980s, 1990s and 2000s, respectively. An increased 5-year survival rate was observed in the colon cancer and rectum cancer patients. Patients older than 60 years of age were more likely to develop colonic cancer (sigmoid) than rectum cancer (49.2% vs. 39.9%). The Cox regression model showed that only rectum cancer survival was related to time duration.

Conclusion

The overall survival and 5-year survival rates showed an increase from the 1960s to 2000s. There is a trend of rightward shift of tumor location in CRC patients.

Comparative proteomic study for profiling differentially expressed proteins between Chinese left- and right-sided colon cancers

The aim of the present study is to profile differentially expressed protein markers between left-sided colon cancer (LSCC) and right-sided colon cancer (RSCC). Fresh tumor tissue samples from LSCC (n = 7) and RSCC (n = 7) groups were analyzed by two-dimensional electrophoresis coupled with MALDI-TOF-MS, followed by Western blotting. In 50 paraffin embedded samples from each group, levels of four differentially expressed proteins (identified by proteomics analysis) were measured by tissue microarray with immunohistochemistry staining to compare the different protein markers between LSCC and RSCC. Sixteen proteins were found to be differentially expressed between LSCC and RSCC. Ten proteins including HSP-60 and PDIA1 were identified to be highly expressed in LSCC (P < 0.01 or P < 0.05), while the expression of six proteins including EEF1D and HSP-27 were higher in RSCC (P < 0.01 or P < 0.05). Virtually all of the indentified proteins were involved in cellular energy metabolism, protein folding/unfolding, and/or oxidative stress. Human colon tumors at various locations have different proteomic biomarkers. Differentially expressed proteins associated with energy metabolism, protein folding/unfolding and oxidative stress contribute to different tumorigenesis, tumor progression, and prognosis between left- and right-sided colon cancer.

Colorectal cancer distribution in 220 Indian patients undergoing colonoscopy

AIM

Colorectal cancer is one of the major cancers in the developed world. The incidence of colorectal cancer is low in India. The aim of the present study was to describe the anatomical distribution and age at diagnosis of colorectal cancer in India.

METHODS

Retrospective descriptive analysis of anatomical distribution, age at diagnosis and demography of 220 cases (149 [67.7%] men) of adenocarcinoma of the colon or rectum diagnosed at colonoscopy over a period of five years.

RESULTS

The mean age at diagnosis was 58.4 years (SD 13.3; range 23-85 years). Twenty-eight (12.7%) cases were below the age of 40 years. The majority (31.8%) cases were aged between 61-70 years. Most of the tumors (n=163, 74%) were located distal to the splenic flexure. Multivariate logistic regression analysis showed that bleeding per rectum (OR 2.8; 95% CI 1.2-6.2) was associated with distal cancer, and palpable mass (OR 3.9; 95% CI 1.7-8.6) was associated with proximal cancer.

CONCLUSIONS

Almost one-third of the colorectal cancers in this series occurred in the seventh decade and were located distal to the splenic flexure.

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.

What is the most cost-effective strategy to screen for second primary colorectal cancers in male cancer survivors in Korea?

AIM

To identify a cost-effective strategy of second primary colorectal cancer (CRC) screening for cancer survivors in Korea using a decision-analytic model.

METHODS

A Markov model estimated the clinical and economic consequences of a simulated 50-year-old male cancer survivors' cohort, and we compared the results of eight screening strategies: no screening, fecal occult blood test (FOBT) annually, FOBT every 2 years, sigmoidoscopy every 5 years, double contrast barium enema every 5 years, and colonoscopy every 10 years (COL10), every 5 years (COL5), and every 3 years (COL3). We included only direct medical costs, and our main outcome measures were discounted lifetime costs, life expectancy, and incremental cost-effectiveness ratio (ICER).

RESULTS

In the base-case analysis, the non-dominated strategies in cancer survivors were COL5, and COL3. The ICER for COL3 in cancer survivors was $5593/life-year saved (LYS), and did not exceed $10,000/LYS in one-way sensitivity analyses. If the risk of CRC in cancer survivors is at least two times higher than that in the general population, COL5 had an ICER of less than $10,500/LYS among both good and poor prognosis of index cancer. If the age of cancer survivors starting CRC screening was decreased to 40 years, the ICER of COL5 was less than $7400/LYS regardless of screening compliance.

CONCLUSION

Our study suggests that more strict and frequent recommendations for colonoscopy such as COL5 and COL3 could be considered as economically reasonable second primary CRC screening strategies for Korean male cancer survivors.

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.

The comparison of the risk factors and clinical manifestations of proximal and distal colorectal cancer

PURPOSE

Colorectal cancers in the proximal or distal site have distinct clinical characteristics. In this study, the authors compared the risk factors of proximal and distal colorectal cancer.

METHODS

A 16-page questionnaire was administered to 529 patients with colorectal cancer before operation. Cancers were classified as proximal or distal relative to the splenic flexure. Of these 529 patients, 6 patients were excluded because of the presence of synchronous colorectal cancers. Data of the 523 patients were analyzed.

RESULTS

Total numbers of proximal and distal cancers were 123 and 400. The proportion of patients with Type 2 diabetes was significantly higher for distal cancer (P = 0.034), whereas a greater proportion of patients with proximal cancer had a gallstone history (P = 0.005). Multivariate analysis revealed Type 2 diabetes to be a risk factor for distal colorectal cancer (P = 0.027) and cholelithiasis to be a risk factor for proximal cancer (P = 0.049). The odds ratio for distal colorectal cancer among males with Type 2 diabetes was 4.1 (95 percent confidence interval, 1.4-12.1). On the other hand, a gallstone history was more associated with proximal colon cancer, especially in females (odds ratio = 5.5; 95 percent confidence interval, 1.4-20.9).

CONCLUSIONS

A comparison of the risk factors of proximal and distal colorectal cancer showed that Type 2 diabetes is associated with distal colorectal cancer in males and that cholelithiasis is associated with proximal colon cancer in females.

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.

Increasing incidence of colorectal cancer in Asia: implications for screening

Many Asian countries, including China, Japan, South Korea, and Singapore, have experienced an increase of two to four times in the incidence of colorectal cancer during the past few decades. The rising trend in incidence and mortality from colorectal cancer is more striking in affluent than in poorer societies and differs substantially among ethnic groups. Although changes in dietary habits and lifestyle are believed to be the reasons underlying the increase, the interaction between these factors and genetic characteristics of the Asian populations might also have a pivotal role. Non-polypoidal (flat or depressed) lesions and colorectal neoplasms arising without preceding adenoma (de novo cancers) seem to be more common in Asian than in other populations. The absence of polypoid growth preceding malignancy has posed difficulties in screening for early colorectal cancer by radiological imaging or even endoscopic techniques. Although epidemiological data are scanty, most Asian populations are not aware of the growing problem of colorectal cancer. More work is needed to elucidate the magnitude of the problem in Asia.

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

BACKGROUND

Colorectal cancer is one of the most common forms of gastrointestinal cancer in the world today. In the Asia-Pacific area, it is the fastest emerging gastrointestinal cancer.

AIM

To determine the basic demographic features of patients with colorectal cancer and the anatomic distribution and characteristics of the tumour in a local Asian population.

METHODS

We conducted a review of consecutive patients who had undergone colonoscopy from 1999 to 2003 at the University of Malaya Medical Center, Kuala Lumpur, Malaysia.

RESULTS

Analysis was carried out on 3404 patients who underwent colonoscopy. A total of 228 patients (7%) were diagnosed with carcinoma. The mean age of diagnosis (+/-s.d.) was 64.4 +/- 13.1 years. The male to female ratio was 1.15. Polyps were noted in 470 patients (14%). Polyps detected concomitantly with a colorectal cancer were noted in 55 patients (2%). Four patients (0.1%) were diagnosed to have familial adenomatous polyposis coli. Of the 228 patients 209 (92%) had tumours at only one site whereas 19 (8%) had synchronous lesions. Tumours were mainly left sided [198 of 248 patients (80%)] with the majority located in the recto-sigmoid region. Detailed records of treatment were available only in 176 patients. A total of 147 of 176 patients (84%) underwent surgery and 50 (28%) also received adjuvant or palliative chemotherapy (28%). Seven of 154 patients (5%) were diagnosed to have stage A cancers, 64 (42%), stage B, 23 (15%), stage C and 60 (39%), stage D. Multivariate analysis using multiple logistic regression analysis showed that age > or =65 years (OR = 1.78; 95% CI: 1.35- 2.36) and Malay (OR = 2.09; 95% CI: 1.30-3.35) and Chinese (OR = 1.77; 95% CI: 1.77-2.69) race were significant independent predictive factors for colorectal cancer.

CONCLUSIONS

The demography of colorectal cancer is different from western patients. Tumours were mainly left sided in our patients. However, no differences in anatomic location were found between races, men and women and younger and older age groups. Colorectal cancer presented in an advanced stage in the majority of patients.

Feasible economic strategies to improve screening compliance for colorectal cancer in Korea

AIM: While colorectal cancer (CRC) is an ideal target for population screening, physician and patient attitudes contribute to low levels of screening uptake. This study was carried out to find feasible economic strategies to improve the CRC screening compliance in Korea.

METHODS: The natural history of a simulated cohort of 50-year-old Korean in the general population was modeled with CRC screening until the age of 80 years. Cases of positive results were worked up with colonoscopy. After polypectomy, colonoscopy was repeated every 3 years. Baseline screening compliance without insurance coverage by the national health insurance (NHI) was assumed to be 30%. If NHI covered the CRC screening or the reimbursement of screening to physicians increased, the compliance was assumed to increase. We evaluated 16 different CRC screening strategies based on Markov model.

RESULTS: When the NHI did not cover the screening and compliance was 30%, non-dominated strategies were colonoscopy every 5 years (COL5) and colonoscopy every 3 years (COL3). In all scenarios of various compliance rates with raised coverage of the NHI and increased reimbursement of colonoscopy, COL10, COL5 and COL3 were non-dominated strategies, and COL10 had lower or minimal incremental medical cost and financial burden on the NHI than the strategy of no screening. These results were stable with sensitivity analyses.

CONCLUSION: Economic strategies for promoting screening compliance can be accompanied by expanding insurance coverage by the NHI and by increasing reimbursement for CRC screening to providers. COL10 was a cost-effective and cost saving screening strategy for CRC in Korea.

Trend of morbidity and mortality of colorectal carcinoma in Nangang District of Harbin from 1992 to 2001

AIM: To determine the epidemiological characteristics of colorectal carcinoma (CRC) morbidity and mortality in Nangang District, Harbin, and to indicate the harmful effect of CRC on the people in that community.

METHODS: The data on morbidity and mortality of CRC in Nangang District (1992-2001) were sorted and coded according to ICD-9 criteria. The crude morbidity and mortality, age-standardized morbidity and mortality (adjusted by the world population), truncated morbidity and mortality (35-64 years old) as well as cumulative rates (0-65 years old) were calculated respectively. Trend u-test and u-test were adopted to analyze the preceding data. The morbidity and mortality in the near future were predicted based on Gray Modeling (GM1, 1).

RESULTS: The CRC morbidity and mortality had been significantly increasing year by year (u = 2.45, P <0.05; u = 1.97, P <0.05 respectively). The morbidity increased from 13.06/100 000 (1992-1993) to 19.37/100 000 (2000-2001) with an average of 4.83% for each year. The mortality for males and females increased from 2.83/100 000, 3.61/100 000 (1992-1993) to 9.60/100 000, 7.90/100 000 (2000-2001) with an anverage of 23.92% (u = 1.47, P >0.05) and 11.88% (u = 1.97, P <0.05) respectively. The age-standardized morbidity (adjusted by the world population) for males and females increased with a rate of 3.24% and 1.19% respectively. And the corresponding rates for mortality were 17.31% and 7.69% respectively. The cumulative and truncated morbidities were also increasing. The cumulative and truncated mortalities increased at an annual rate of 26.00%, 24.95% for males and 11.67%, 10.87 for females. The predicted morbidity and mortality were 28.15/100 000, 13.43/100 000 for males and 24.16/100 000, 20.45/100 000 for females respectively in 2006.

CONCLUSION: The morbidity and mortality of CRC have increased in 1992-2001, and will keep on increasing in the future, which are expected to reach 26.12/100 000 and 17.43/100 000 in 2006, respectively.

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