Reduction of the incidence and mortality of rectal cancer by polypectomy: a prospective cohort study in Haining County

Epidemiology and early screening strategies for colorectal cancer in China

China ranks the first worldwide in the number of new colorectal cancer (CRC) cases and CRC-related deaths. The increasing incidence of early-onset CRC in recent years highlights the challenges related to CRC screening and prevention. High-quality colonoscopy is the universally used gold standard for CRC screening. Risk assessment combined with a two-step screening strategy based on colonoscopy and non-invasive examinations was proven to be highly effective. However, systematic use of well-established risk factors associated with CRC, beyond age, could better identify those who might harbor advanced colorectal neoplasia, improve the diagnostic yield of current screening modalities, and optimize the selection of individuals who might benefit most from preventive strategies. "Personalization" and "Standardization" are the future development directions of CRC screening, from the initiation of screening in those at high risk for CRC to follow-up after treatment, which are the key to ensure the screening efficiency.

Clinical evaluation of a multitarget fecal immunochemical test-sDNA test for colorectal cancer screening in a high-risk population: a prospective, multicenter clinical study

Colorectal cancer (CRC) is a major malignancy threatening the health of people in China and screening could be effective for preventing the occurrence and reducing the mortality of CRC. We conducted a multicenter, prospective clinical study which recruited 4,245 high-risk CRC individuals defined as having positive risk-adapted scores or fecal immunochemical test (FIT) results, to evaluate the clinical performance of the multitarget fecal immunochemical and stool DNA (FIT-sDNA) test for CRC screening. Each participant was asked to provide a stool sample prior to bowel preparation, and FIT-sDNA test and FIT were performed independently of colonoscopy. We found that 186 (4.4%) were confirmed to have CRC, and 375 (8.8%) had advanced precancerous neoplasia among the high CRC risk individuals. The sensitivity of detecting CRC for FIT-sDNA test was 91.9% (95% CI, 86.8-95.3), compared with 62.4% (95% CI, 54.9-69.3) for FIT (P < 0.001). The sensitivity for detecting advanced precancerous neoplasia was 63.5% (95% CI, 58.3-68.3) for FIT-sDNA test, compared with 30.9% (95% CI, 26.3-35.6) for FIT (P < 0.001). Multitarget FIT-sDNA test detected more colorectal advanced neoplasia than FIT. Overall, these findings indicated that in areas with limited colonoscopy resources, FIT-sDNA test could be a promising further risk triaging modality to select patients for colonoscopy in CRC screening.

Microsimulation Model for Prevention and Intervention of Coloretal Cancer in China (MIMIC-CRC): Development, Calibration, Validation, and Application

Introduction

A microsimulation model provides important references for decision-making regarding colorectal cancer (CRC) prevention strategies, yet such a well-validated model is scarce in China.

Methods

We comprehensively introduce the development of MIcrosimulation Model for the prevention and Intervention of Colorectal Cancer in China (MIMIC-CRC). The MIMIC-CRC was first constructed to simulate the natural history of CRC based on the adenoma-carcinoma pathway. The parameters were calibrated and validated using data from population-based cancer registry data and CRC screening programs. Furthermore, to assess the model’s external validity, we compared the model-derived results to outcome patterns of a sigmoidoscopy screening trial in the UK [UK Flexible Sigmoidoscopy Screening (UKFSS) trial]. Finally, we evaluated the application potential of the MIMIC-CRC model in CRC screening by comparing the 8 different strategies.

Results

We found that most of the model-predicted colorectal lesion prevalence was within the 95% CIs of observed prevalence in a large population-based CRC screening program in China. In addition, model-predicted sex- and age-specific CRC incidence and mortality were equivalent to the registry-based data. The hazard ratios of model-estimated CRC-related incidence and mortality for sigmoidoscopy screening compared to no screening were 0.60 and 0.51, respectively, which were comparable to the reported results of the UKFSS trial. Moreover, we found that all 8 strategies could reduce CRC incidence and mortality compared to no screening.

Conclusions

The well-calibrated and validated MIMIC-CRC model may represent a valid tool to assess the comparative effectiveness of CRC screening strategies and will be useful for further decision-making to CRC prevention.

Preoperative Diagnostic Uncertainty in T2-T3 Rectal Adenomas and T1-T2 Adenocarcinomas and a Therapeutic Dilemma: Transanal Endoscopic Surgery, or Total Mesorectal Excision?

BACKGROUND

Endorectal ultrasound and rectal magnetic resonance are sometimes unable to differentiate between stages T2 and T3 in rectal adenomas that are possible adenocarcinomas, or between stages T1 and T2 in rectal adenocarcinomas. These cases of diagnostic uncertainty raise a therapeutic dilemma: transanal endoscopic surgery (TES) or total mesorectal excision (TME)?

METHODS

An observational study of a cohort of 803 patients who underwent TES from 2004 to 2021. Patients operated on for adenoma (group I) and low-grade T1 adenocarcinoma (group II) were included. The variables related to uncertain diagnosis, and to the definitive pathological diagnosis of adenocarcinoma stage higher than T1, were analyzed.

RESULTS

A total of 638 patients were included. Group I comprised 529 patients, 113 (21.4%) with uncertain diagnosis. Seventeen (15%) eventually had a pathological diagnosis of adenocarcinoma higher than T1. However, the variable diagnostic uncertainty was a risk factor for adenocarcinoma above T1 (OR 2.3, 95% CI 1.1-4.7). Group II included 109 patients, eight with uncertain diagnosis (7.3%). Two patients presented a definitive pathological diagnosis of adenocarcinoma above T1.

CONCLUSIONS

On the strength of these data, we recommend TES as the initial indication in cases of diagnostic uncertainty. Multicenter studies with larger samples for both groups should now be performed to further assess this strategy of initiating treatment with TES.

Epidemiology and risk factors of colorectal cancer in China

In China, colorectal cancer (CRC) ranked fourth and fifth in the highest incidence and mortality rates of all malignancies in 2018, respectively. Although these rates are below the world average, China placed first worldwide in the number of new CRC cases and CRC-related deaths because of its comparatively large population. This disease represents a threat to the health of population and incurs a heavy economic burden on the society and individuals. CRC has various risk factors, including age, sex, lifestyle, genetic factors, obesity, diabetes, gut microbiota status, and precancerous lesions. Furthermore, incidence and mortality rates of CRC are closely related to socioeconomic development levels, varying according to regional and population characteristics. Prevention is the main strategy to reduce incidence and mortality rates of CRC. This can be achieved through strategies stimulating lifestyle changes, healthy diet habits, and early screening for high-risk individuals. To reduce the burden of CRC, public health officials should promote prevention and management of modifiable risk factors through national policies. The rising incidence and mortality rates of CRC in China may be timely curbed by clarifying specific epidemiological characteristics, optimizing early screening strategies, and strictly implementing diagnosis and treatment guidelines. Thus, this study aimed to collect and report the current research status on epidemiology and risk factors of CRC in China.

Strategies for prevention of gastrointestinal cancers in developing countries: a systematic review

Background

Gastrointestinal cancers account for one third of total cancer incidence and mortality in developing countries. To date, there is no systematic synthesis of evidence regarding strategies to prevent gastrointestinal cancers in developing countries. We aimed to provide a systematic overview of studies evaluating strategies for prevention or early detection of the three most common gastrointestinal cancers (gastric, liver and colorectal cancer) in developing countries.

Methods

We searched MEDLINE, Web of Science and WHO Global Index Medicus databases for relevant articles published until October 2016 using combinations of the search terms “gastrointestinal”, “digestive system”, “gastric”, “liver”, “colorectal”, “cancer”, “prevention”, “early detection” and “developing country” (including names).

Results

Overall, 73 articles met the inclusion criteria, providing information on short– and long–term outcomes (up to 30 years) from various intervention studies (∼45% randomized). Trials on hepatitis B vaccination consistently showed vaccine efficacy over time and indicated long–term preventive effects on liver cancer incidence that start to become measurable at the population level. Studies on anti–H. pylori treatment suggested a reduction in gastric cancer incidence reaching statistical significance after long–term follow–up, while evidence regarding a preventive effect in persons with precancerous lesions is still inconclusive. The studies regarding colorectal cancer focused on early detection, ∼90% of which were restricted to intermediate endpoints.

Conclusion

In conclusion, there were a number of studies on gastric and liver cancer prevention in developing countries showing promising results after long–term follow–up. Important next steps include pooled meta–analyses as far as possible given the heterogeneity between studies as well as implementation research.

Californium-252 neutron intracavity brachytherapy alone for T1N0 low-lying rectal adenocarcinoma: A definitive anal sphincter-preserving radiotherapy

This study evaluated the 4-year results of 32 patients with T1N0 low-lying rectal adenocarcinoma treated solely with californium-252 (Cf-252) neutron intracavity brachytherapy (ICBT). Patients were solicited into the study from January 2008 to June 2011. All the patients had refused surgery or surgery was contraindicated. The patients were treated with Cf-252 neutron ICBT using a novel 3.5-cm diameter off-axis 4-channel intrarectal applicator designed by the authors. The dose reference point was defined on the mucosa surface, with a total dose of 55-62 Gy-eq/4 f (13-16 Gy-eq/f/wk). All the patients completed the radiotherapy in accordance with our protocol. The rectal lesions regressed completely, and the acute rectal toxicity was mild (≤G2). The 4-year local control, overall survival, disease-free survival, and late complication (≥G2) rates were 96.9%, 90.6%, 87.5% and 15.6%, respectively. No severe late complication (≥G3) occurred. The mean follow-up was 56.1 ± 16.0 months. At the end of last follow-up, 29 patients remained alive. The mean survival time was 82.1 ± 2.7 months. Cf-252 neutron ICBT administered as the sole treatment (without surgery) for patients with T1N0 low-lying rectal adenocarcinoma is effective with acceptable late complications. Our study and method offers a definitive anal sphincter-preserving radiotherapy for T1N0 low-lying rectal adenocarcinoma patients.

Transanal endoscopic surgery with total wall excision is required with rectal adenomas due to the high frequency of adenocarcinoma

BACKGROUND

Colorectal adenomatous polyps are considered premalignant lesions, although a high percentage are already malignant at the time of their removal. Full-thickness excision in patients with adenoma detected in preoperative biopsy enables much more accurate pathology examination and has shown that local surgery is appropriate for T1 adenocarcinoma.

OBJECTIVE

To determine whether full-thickness excision during transanal endoscopic surgery is the treatment of choice for rectal adenoma, and to identify possible predictors of invasive adenocarcinoma associated with this type of lesion.

DESIGN

Prospective, observational study.

SETTING

The study was conducted at a university teaching hospital.

PATIENTS

All patients scheduled for transanal endoscopic surgery after detection of adenoma in a preoperative biopsy between June 2004 and February 2013 entered the study.

MAIN OUTCOME MEASURES

The principal variable was the presence of invasive adenocarcinoma in the pathology study. Other study variables were the epidemiological variables sex and age; the clinical variables tumor size, number of quadrants affected, distance from the anal verge, and tumor location; and the morphological variables tumor aspect, degree of dysplasia, preoperative biopsy (tubulo-villous), endorectal ultrasound, and pelvic MRI stage. Variables found to be related to the risk of malignancy in rectal adenomas were evaluated using univariate and multivariate analysis.

RESULTS

Of 471 patients who underwent surgery, 277 had a preoperative diagnosis of adenoma. Final pathology studies showed 52 (18.8%) invasive adenocarcinomas, among which 27 were pT1 (52%), 16 pT2 (30.7%), and 9 pT3 (17.3%). Factors predictive of invasive adenocarcinoma were sessile morphology (OR 3.2, 95%CI 1.4-7.1), high-grade dysplasia (OR 2.3, 95%CI 1.2-4.8), and endorectal ultrasound stage uT2-T3 (OR 3.8, 95%CI 1.6-9).

LIMITATIONS

The limitations are derived from the observational design.

CONCLUSIONS

In this sample, half of the adenocarcinomas from adenomas were T1 adenocarcinomas. Because a high proportion of rectal adenomas are, in fact, invasive adenocarcinomas, full-thickness excision is appropriate.

Consensus on the Prevention, Screening, Early Diagnosis and Treatment of Colorectal Tumors in China: Chinese Society of Gastroenterology, October 14-15, 2011, Shanghai, China

BACKGROUND

Colorectal cancer (CRC) is steadily increasing in China. Colorectal adenoma (CRA) is the most important precancerous disease of CRC. Screening for colorectal tumors can aid early diagnosis. Advances in endoscopic mucosal resection and endoscopic submucosal dissection can aid the early treatment of colorectal tumors. Furthermore, because of high risk of recurrence after removal of adenomas under endoscopy, factors contributing to recurrence, the follow-up mode and the interval established, and the feasibility of application and the time of various chemical preventions should be concerned. However, a relevant consensus on the screening, early diagnosis and treatment, and prevention of colorectal tumors in China is lacking.

SUMMARY

The consensus recommendations include epidemiology, pathology, screening, early diagnosis, endoscopic treatment, monitoring and follow-up, and chemoprevention of colorectal tumors in China.

KEY MESSAGE

This is the first consensus on the prevention, screening, early diagnosis and treatment of CRA and CRC in China based on evidence in the literature and on local data.

PRACTICAL IMPLICATIONS

Through reviewing the literature, regional data and passing the consensus by an anonymous vote, gastroenterology experts from all over China launch the consensus recommendations in Shanghai. The incidence and mortality of CRC in China has increased, and the incidence or detection rate of CRA has increased rapidly. Screening for colorectal tumors should be performed at age 50-74 years. Preliminary screening should be undertaken to find persons at high risk, followed by colonoscopy. A screening cycle of 3 years is recommended for persistent interventions. Opportunistic screening is a mode suitable for the current healthcare system and national situation. Colonoscopy combined with pathological examination is the standard method for the diagnosis of colorectal tumors. CRA removal under endoscopy can prevent CRC to some extent, but CRA has an obvious recurrence trend. The follow-up interval after the removal or surgery of colorectal tumors should be different with lesions. Primary prevention of CRA includes improved diet with more fiber, supplements containing calcium and vitamin D, supplements containing folic acid for those with low hemoglobin levels, and cessation of tobacco smoking. Non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors have been recognized to prevent recurrence after adenoma removal.

Factors influencing quality of bowel preparation for colonoscopy

Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance. However, the utility of these technological advancements remain dependent on the quality of bowel preparation during colonoscopy. Poor bowel preparation has been shown to be associated with lower quality indicators of colonoscopy performance, such as reduced cecal intubation rates, increased patient discomfort and lower adenoma detection. The most popular bowel preparation regimes currently used are based on either Polyethylene glycol-electrolyte, a non-absorbable solution, or aqueous sodium phosphate, a low-volume hyperosmotic solution. Statements from various international societies and several reviews have suggested that the efficacy of bowel preparation regimes based on both purgatives are similar, although patients’ compliance with these regimes may differ somewhat. Many studies have now shown that factors other than the type of bowel preparation regime used, can influence the quality of bowel preparation among adult patients undergoing colonoscopy. These factors can be broadly categorized as either patient-related or procedure-related. Studies from both Asia and the West have identified patient-related factors such as an increased age, male gender, presence of co-morbidity and socio-economic status of patients to be associated with poor bowel preparation among adults undergoing routine out-patient colonoscopy. Additionally, procedure-related factors such as adherence to bowel preparation instructions, timing of bowel purgative administration and appointment waiting times for colonoscopy are recognized to influence the quality of colon cleansing. Knowledge of these factors should aid clinicians in modifying bowel preparation regimes accordingly, such that the quality of colonoscopy performance and delivery of service to patients can be optimised.

Performance of a colorectal cancer screening protocol in an economically and medically underserved population

The performance of combining fecal immunochemical tests (FITs) and a high-risk factor questionnaire (HRFQ) in colorectal cancer (CRC) screening in economically and medically underserved populations is uncertain. This study investigated the performance of a CRC screening protocol of combining FITs and an HRFQ as primary screening methods in a rural Chinese population. A CRC mass screening was conducted using FITs and an HRFQ as the first and colonoscopy as the second stage of screening in Jiashan, 2007-2009. The target population was 31,963 residents in three communities. The compliance was 84.7% for HRFQ, 76.4% for FITs, and 78.7% for colonoscopy. The detected rates of cancer, adenoma, nonadenomatous polyps, and advanced neoplasm were 2.7%, 14.8%, 5.9%, and 8.9% by FITs, which were higher than those by HRFQ (0.5%, 9.2%, 4.8%, and 3.8%, respectively). There was no significant difference in detected rate for nonadenomatous polyps between FITs and HRFQ. A total of 41.2% adenomas, 53.2% nonadenomatous polyps, and 29.8% advanced neoplasms were detected by HRFQ but missed by FITs. Positive predictive value of the screening protocol of combining FITs and HRFQ for advanced neoplasm was 5.7%, which was higher than FITs alone. Men had a higher prevalence of advanced neoplasm than women. Results indicate that combining FITs and HRFQ as primary screening methods is an efficient CRC screening strategy in economically and medically underserved populations.

Aspectos epidemiológicos dos pólipos e lesões plano-elevadas colorretais

INTRODUÇÃO: Os pólipos e as lesões plano-elevadas colorretais são importantes na prevenção do câncer colorretal pelo risco de malignização dos adenomas. OBJETIVO: traçar o perfil demográfico dos pacientes com diagnóstico endoscópico de pólipos e/ou lesões plano-elevadas colorretais no Hospital Universitário da Universidade Federal de Sergipe e Torres Centro Médico. MÉTODOS: Foram avaliados 6.919 prontuários de 2002 a 2007, enfatizando-se as variáveis: idade, gênero, procedência e indicação; número, tamanho, morfologia, histologia, grau de displasia, topografia, lesões sincrônicas e metacrônicas, e diagnósticos associados. RESULTADOS: Foram encontradas 1.031 (13,51%) lesões em 935 exames, correspondendo a 826 pacientes, 46% masculino e 54% feminino. A idade variou de 3 a 96 anos, com média de 53,64. A distribuição topográfica mais frequente das lesões polipoides foi em reto e sigmoide (58,40%). As lesões eram sésseis em 52,80%, pediculadas em 27,90% e plano-elevadas em 19,30% dos casos. Ocorreram lesões sincrônicas em 23,48% e metacrônicas em 30,10% dos pacientes. Histologicamente, 43,36% eram adenomas, sendo 85,70% tubulares, 9,60% tubulo-vilosos e 4,70% vilosos; 30,64% eram pólipos hiperplásicos, 15,80% inflamatórios e 10,20% possuíam outros tipos histológicos. Os adenomas apresentavam displasia de baixo grau em 83,40% dos casos e alto grau em 16,60%. Sete eram adenocarcinomas, um carcinoide e um tumor gastrointestinal estromal. CONCLUSÕES: A colonoscopia e a polipectomia são importantes no diagnóstico e prevenção do câncer colorretal.

Barrier-focused intervention to increase colonoscopy attendance among nonadherent high-risk populations

AIM: To increase attendance for colonoscopy among nonadherent high-risk individuals for colorectal cancer (CRC) screening in China.

METHODS: During the first 12 mo without intervention, only 428 of the 2398 high-risk subjects attended a scheduled colonoscopy examination. The 1970 subjects who did not attend for CRC screening were enrolled in the present study. Prior barrier investigation was performed to ascertain the reasons for nonadherence. A barrier-focused intervention program was then established and implemented among eligible nonadherent subjects by telephone interviews and on-site consultations. The completion rates of colonoscopy during the first 12 mo without intervention and the second 12 mo with intervention were compared. Variations in the effect of the intervention on some high-risk factors and barrier characteristics were analyzed using logistic regression.

RESULTS: 540 subjects who were not eligible were excluded from the study. The colonoscopy attendance rate was 23.04% (428/1858) during the first 12 mo without intervention, and 37.69% (539/1430) during the second 12 mo with intervention (P < 0.001). Logistic regression analysis showed that the intervention was more effective among subjects with only objective barriers (OR: 34.590, 95% CI: 23.204-51.563) or subjects with some specific high-risk characteristics: first-degree relatives diagnosed with CRC (OR: 1.778, 95% CI: 1.010-3.131), personal history of intestinal polyps (OR: 3.815, 95% CI: 1.994-7.300) and positive result for immunochemical fecal occult blood testing (OR: 2.718, 95% CI: 1.479-4.996).

CONCLUSION: The barrier-focused telephone or on-site consultation intervention appears to be a feasible means to improve colonoscopy attendance among nonadherent high-risk subjects for CRC screening in China.

Transanal endoscopic microsurgery versus endoscopic mucosal resection for large rectal adenomas (TREND-study)

Background

Recent non-randomized studies suggest that extended endoscopic mucosal resection (EMR) is equally effective in removing large rectal adenomas as transanal endoscopic microsurgery (TEM). If equally effective, EMR might be a more cost-effective approach as this strategy does not require expensive equipment, general anesthesia and hospital admission. Furthermore, EMR appears to be associated with fewer complications.

The aim of this study is to compare the cost-effectiveness and cost-utility of TEM and EMR for the resection of large rectal adenomas.

Methods/design

Multicenter randomized trial among 15 hospitals in the Netherlands. Patients with a rectal adenoma ≥ 3 cm, located between 1–15 cm ab ano, will be randomized to a TEM- or EMR-treatment strategy. For TEM, patients will be treated under general anesthesia, adenomas will be dissected en-bloc by a full-thickness excision, and patients will be admitted to the hospital. For EMR, no or conscious sedation is used, lesions will be resected through the submucosal plane in a piecemeal fashion, and patients will be discharged from the hospital. Residual adenoma that is visible during the first surveillance endoscopy at 3 months will be removed endoscopically in both treatment strategies and is considered as part of the primary treatment.

Primary outcome measure is the proportion of patients with recurrence after 3 months. Secondary outcome measures are: 2) number of days not spent in hospital from initial treatment until 2 years afterwards; 3) major and minor morbidity; 4) disease specific and general quality of life; 5) anorectal function; 6) health care utilization and costs. A cost-effectiveness and cost-utility analysis of EMR against TEM for large rectal adenomas will be performed from a societal perspective with respectively the costs per recurrence free patient and the cost per quality adjusted life year as outcome measures.

Based on comparable recurrence rates for TEM and EMR of 3.3% and considering an upper-limit of 10% for EMR to be non-inferior (beta-error 0.2 and one-sided alpha-error 0.05), 89 patients are needed per group.

Discussion

The TREND study is the first randomized trial evaluating whether TEM or EMR is more cost-effective for the treatment of large rectal adenomas.

Trial registration number

(trialregister.nl) NTR1422

Establishment and characterization of a cell line HRC-99 from human rectal adenocarcinoma

AIM: To establish a cell line from human moderately differentiated rectal adenocarcinoma, and to investigate its biological characteristics.

METHODS: Cancer tissues taken from freshly resected specimens of patients with primary rectal adenocarcinoma were incubated in vitro. The cell line, we named HRC-99, was established. The biological characteristics of these cells were studied by light microscopy, electron microscopy, immunohistochemistry, chromosome analysis and heterogenic transplantation experiment.

RESULTS: Cells from specimens of the primary tumor, the HRC-99 cell line and transplanted tumor were confirmed possessing the characteristics of malignant glandular epithelium under light and electron microscope. The cell growth curve, duplicating time and cleavage index in vitro were also observed. CEA and CK-20 were positively expressed in the cells. Nuclear chromosome analysis revealed that the tumor was a subtriploid with a mode of 60 per cell, and marker chromosome and chromosome translocation were found in G band as well. Tumor nodes were induced under the skin of nude mice by heterogenic transplantation.

CONCLUSION: The HRC-99 cell line is a new cell line out of rectal moderately differentiated adenocarcinoma.

Virtual colonography: identification and differentiation of colorectal lesions using multi-detector computed tomography

OBJECTIVE

Early detection of precancerous or malignant lesions may be decisive for prognosis of patients with colorectal cancer. In this prospective feasibility study, multi-detector spiral computed tomography (CT) colonography was compared with conventional colonoscopy for the detection of colorectal polyps.

MATERIAL AND METHODS

Seventy-eight patients underwent CT colonography (standard colonoscopy preparation, distension with room air, prone and supine position) immediately before colonoscopy. Sixty-five (83%) were asymptomatic screening subjects, while the rest had symptoms suggestive of colorectal disease. Presence, location, and size of lesions were prospectively assessed. Sensitivity, specificity, and positive and negative predictive values of CT colonography were calculated using conventional colonoscopy as the reference standard.

RESULTS

Conventional colonoscopy was normal in 52 patients. In 26 patients a total of 49 polyps and 3 carcinomas were identified. All three carcinomas and 39 polyps (80%) were identified by CT colonography. Seven of 7 polyps > or = 10 mm (100%), 13 of 16 polyps of 6 to 9 mm (81%), and 19 of 26 polyps < or = 5 mm (73%) in diameter were identified. Fourteen false-positive findings (10 of which were < or = 5 mm in diameter) were related to 8 patients (specificity at the patient level was 86%). In 10 patients, a total of 10 polyps were missed by CT colonography, 7 of which were < or = 5 mm in diameter.

CONCLUSIONS

In this feasibility study, multi-detector spiral CT colonography allows accurate detection of polyps > 5 mm in diameter, but at the expense of low specificity in the small size range.

Transformation of immortalized colorectal crypt cells by microcystin involving constitutive activation of Akt and MAPK cascade

It has been shown by epidemiological and animal studies that microcystin is an important exogenous factor involved in the carcinogenesis of colorectal cancer (CRC). However, details of the mechanism remain unclear. Transformation of colorectal cells is an important initial step in carcinogenesis. Whether microcystin is capable of transforming immortalized colorectal crypt cells, and what the mechanism might be, was investigated. In the present study, we demonstrated that immortalized colorectal crypt cells could be transformed by microcystin. Transformed colorectal crypt cells showed an anchorage-independent growth phenotype, and the proliferation activities of microcystin-transformed cells were also greater than that of immortalized colorectal crypt cells. The Akt and the p38, JNK of mitogen-activated protein kinase (MAPK) pathways in microcystin-transformed cells were found to be constitutively activated. In microcystin-transformed cells, PI3K, MAPKAPK2, Akt, cyclin D1 and cyclin D3 in the Akt pathway; IQGAP-2, RabGTPase, Rap1GAP, RasGAP, R-Ras, Krev-1 and TC21 of the Ras GTP/GDP protein family; and A-Raf, B-Raf and PAK in the Ras/MAPK pathway were all markedly upregulated. However, in positive control cells, dimethylhydrazine-transformed cells, only the Akt pathway was activated by PI3K, and no evidence of alteration of any molecules of the Ras superfamily was observed. Inhibition of Akt, p38 and JNK activation led to a reduced proliferation of microcystin-transformed cells. This implies that the constitutive activation of Akt and the p38, JNK of MAPK pathways in microcystin-transformed cells may be the mechanism by which this important external factor acts in the carcinogenesis of CRC.

Clinical significance of carcinoembryonic antigen detection in rectal cancer patients with total mesorectal excision

AIM: To detect the carcinoembryonic antigen (CEA) in rectal cancer patients with total mesorectal excision (TME), and to prove the significance of TME in the treatment of rectal cancer.

METHODS: Pathological specimens were sellected from tissues of cancer, distal mesorectal margin (DMM), circumferential resection margin (CRM) and outer pelvic fascia in rectal cancer (n = 52) patients with TME. CEA was detected in these specimens using immunohistocheminical method, and the data were analyzed with SPSS software.

RESULTS: CEA expression was significantly higher in tissues of rectal cancer (47/52) than that in normal tissuess (2/20). There was significant difference between them (P < 0.001). CEA expression also existed in tissue of CRM (8/52). However, no CEA expression was observed in tissues of DMM and outer pelvic fascia.

CONCLUSION: CEA is highly expressed in tissues of rectal cancer. This provides scientific evidence for TME in the treatment of rectal cancer.

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.

Anatomic pathology of tumor cell spread through lymph nodes in the mesorectum of rectal cancer

AIM: To investigate the size, distribution, and pattern of metastases and micrometastases of lymph nodes (LNs) within the mesorectum of rectal cancer.

METHODS: All rectal cancer specimens obtained by total mesorectal excision were treated with lymph node revealing solution to retrieve all LNs, which were detected with a combination use of haematoxylin and eosin staining and immunohistochemical (IHC) staining with an antibody against cytokeratin 20.

RESULTS: A total of 548 LNs in 31 specimens were harvested, with 17.7 nodes per case. 153 nodes (27.9%) in 27 patients (87.1%) were found positive by routine pathological examination and IHC staining. Of all the nodes retrieved, nodes <0.5 cm numbered 366 (66.8%) with 91 (59.5%) positive. Among the 27 metastasized cases, there were 15 cases whose tumors were located in the back wall of the rectum, in which 78 nodes were detected positive with 75 nodes along the superior rectal artery. In the other 12 cases with tumors positioned in the lateral wall, 75 nodes were diagnosed positive, with 37 nodes, 8 nodes around the branch of superior rectal artery and middle rectal artery on tumor side, and 9 nodes, 0 nodes on the opposite side, respectively.

CONCLUSION: The majority of tumor positive LNs in the mesorectum are <0.5 cm in diameter. LNs within the mesorectum are distributed mainly along major supplying vessels with around the superior rectal artery most. The pattern of lymphatic spread of rectal cancer has close relationships with tumor location in the rectal wall. Tumors in the posterior wall may spread in both sides of the mesorectum simultaneously, while tumors localized in one lateral wall tend to metastasize preferably to LNs in the mesorectum of tumor side.

Comparative evaluation of immune response after laparoscopical and open total mesorectal excisions with anal sphincter preservation in patients with rectal cancer

AIM: The study of immune response of open versus laparoscopical total mesorectal excision with anal sphincter preservation in patients with rectal cancer has not been reported yet. The dissected retroperitoneal area that contacts directly with carbon dioxide is extensive in laparoscopic total mesorectal excision with anal sphincter preservation surgery. It is important to clarify whether the immune response of laparoscopic total mesorectal excision with anal sphincter preservation (LTME with ASP) in patients with rectal cancer is suppressed more severely than that of open surgery (OTME with ASP). This study was designed to compare the immune functions after laparoscopic and open total mesorectal excision with anal sphincter preservation for rectal cancer.

METHODS: This study involved 45 patients undergoing laparoscopic (n = 20) and open (n = 25) total mesorectal excisions with anal sphincter preservation for rectal cancer. Serum interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor α (TNF_α) were assayed preoperatively and on days 1 and 5 postoperatively. CD3⁺ and CD56⁺ T lymphocyte count, CD3^- and CD56⁺ natural killer cell (NK) count and immunoglobulin (IgG/IgM/IgA) were assayed preoperatively and on day 5 postoperatively. The numbers of CD3⁺ and CD56⁺ T lymphocytes and CD3^- and CD56⁺ NK cells were counted using flow cytometry. An enzyme-linked immunosorbent assay (ELISA) was used for IL-2, IL-6 and TNF_α determination. And IgG, IgM, and IgA were assayed using immunonephelometry.

RESULTS: The demographic data of the two groups had no difference. The preoperative levels of CD3⁺ and CD56⁺ T lymphocyte count, CD3^- and CD56⁺ NK count, serum IgG, IgM, IgA, IL-2, IL-6 and TNF_α also had no significant difference in the two groups (P > 0.05). The CD3⁺ and CD56⁺ T lymphocyte counts had no obvious changes after surgery in laparoscopic (d = -0.79% ± 3.83%) and open (d = 0.42% ± 2.09%) groups. The CD3^- and CD56⁺ NK counts were decreased postoperatively in both laparoscopic (d = -7.23% ± 11.33%) and open (d = -9.21% ± 13.93%) groups. The differences of the determined values of serum IgG, IgM and IgA on the fifth day after operation subtracted those before operation were -2.56 ± 2.14 g/L, -252.35 ± 392.94 mg/L, -506.15 ± 912.24 mg/L in laparoscopic group, and -1.81 ± 2.10 g/L, -282.72 ± 356.75 mg/L, -252.20 ± 396.28 mg/L in open group, respectively. The levels of IL-2 were decreased after operation in both groups. However, the levels of IL-6 were decreased after laparoscopic surgery (d₁ = -23.14 ± 263.97 ng/L and d₅ = -40.08 ± 272.03 ng/L), and increased after open surgery (d₁ = 27.38 ± 129.14 ng/L and d₅ = 21.67 ± 234.31 ng/L). The TNF_α levels were not elevated after surgery in both groups. There were no significant differences in the numbers of CD3⁺ and CD56⁺ T lymphocytes and CD3^- and CD56⁺ NK cells, the levels of IgG, IgM, IgA, IL-2, IL-6 and TNF_α between the two groups (P > 0.05).

CONCLUSION: There are no differences in immune responses between the patients having laparoscopic total mesorectal excision with anal sphincter preservation and those undergone open surgery for rectal cancer.

Anatomic site distribution and clinic pathologic characteristics of colorectal cancer in young Chinese

AIM

To study the anatomic site distribution and pathologic characteristics of colorectal cancer (CRC) in young Chinese.

METHODS

A retrospective study was undertaken. Data were collected from 1 370 patients in Nan Fang Hospital from 1974 to 1999, including 309 patients younger than 40 years and 1 061 patients older than 40 years. The median age was 54 years. All patients with colorectal adenocarcinomas were diagnosed by histology and underwent surgery.

RESULTS

Overall, 22.3% (309/1370) of CRC patients were young people. The proportion of males in the young group was 57.0% vs 58.3% in the aged group (P>0.05, x² = 0.16). 24.1% of young group vs 25.1% of aged group had lesions in the proximal colon and 72.4% vs 71.2% had cancers located in distal colorectum (P>0.05, x² = 0.42). Adenocarcinoma was the most common histologic type in both groups. 71.5% of young group vs 83.4% of aged group was adenocarcinoma (P <0.01, x² = 18.09), 17.4% vs 12.0% was mucinous adenocarcinoma (P<0.05, x²=4.70) and 5.5% vs 1.1% was signet-ring cell carcinoma (P<0.01, x² = 30.20). 18.2% of young group vs 24.9% of aged group was early stage (Duke's stage A) and 81.9% vs 75.1% was advanced stage (Duke's stage B, C, D) (P <0.05, x² = 5.13). 20.9% of young group vs 11.1% of aged group was poor differentiation (P<0.01, x² = 14.75) and 59.5% vs 34.3% had lymphatic metastasis (P<0.01, x² = 53.25).

CONCLUSION

CRC of young people has no significant difference from middle-aged and old people in either gender distribution or anatomic site distribution, but the former has some clinical pathologic characteristics that are different from the latter. CRC in young people has relatively worse prognosis. The therapeutic effects depend on paying attention to these clinical pathologic characteristics and early diagnosis and early treatment.

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Continuous release of interleukin 12 from microencapsulated engineered cells for colon cancer therapy

AIM: To explore the anti-tumor immunity against CT26 colon tumor of the microencapsulated cells modified with murine interleukine-12 (mIL-12) gene.

METHODS: Mouse fibroblasts (NIH3T3) were stably transfected to express mIL-12 using expression plasmids carrying mIL-12 gene (p35 and p40), and NIH3T3-mIL-12 cells were encapsulated in alginate microcapsules for long-term delivery of mIL-12. mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells was confirmed using ELISA assay. Transplantation of the microencapsulated NIH3T3-mIL-12 cells was performed in the tumor-bearing mice with CT26 cells. The anti-tumor responses and the anti-tumor activities of the microencapsulated NIH3T3-mIL-12 cells were evaluated.

RESULTS: Microencapsulated NIH3T3-mIL-12 cells could release mIL-12 continuously and stably for a long time. After the microencapsulated NIH3T3-mIL-12 cells were transplanted subcutaneously into the tumor-bearing mice for 21 d, the serum concentrations of mIL-12, mIL-2 and mIFN-γ, the cytotoxicity of the CTL from the splenocytes and the NK activity in the treatment group were significantly higher than those in the controls. Moreover, mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells resulted in a significant inhibition of tumor proliferation and a prolonged survival of tumor-bearing mice.

CONCLUSION: The microencapsulated NIH3T3-mIL-12 cells have a significant therapeutic effect on the experimental colon tumor by activating anti-tumor immune responses in vivo. Microencapsulated and genetically engineered cells may be an extremely versatile tool for tumor gene therapy.

Local excision carcinoma in early stage

AIM

To assess the validity of local excision for the early stage low rectal cancer as an effective treatment alternative to radical resection.

METHODS

A retrospective medical chart review was done in 47 patients with early stage low rectal carcinoma who underwent local excision from November 1980 through November 1999 at Cancer Hospital of Chinese Academy of Medical Sciences (CAMS). The patients were treated by either transanal (40 cases), trans-sacral (5 cases), or trans-vaginal (2 cases) excision of tumors and no death was related to surgery. Sixteen patients received postoperative radiotherapy.

RESULTS

T1 and T2 lesion was found in 36 (76.6 %) and 11 patients (23.4 %) respectively. The overall local tumor recurrence rate was 14.9 % (7/47), with an average recurrence time of 21 months. Among these 7 recurrent patients, there were 4 T1 and 3 T2 lesions. Microscopically, the surgical incisal margin was negative in 45 (95.7 %) and positive in 2 patients (4.3 %); Both of the later had developed local recurrence. The overall 5-year survival rate was 91.7 %, in which there were 94.4 % for T1 and 83.3 % for T2 tumors. T stage, intravessel tumor thrombosis, lymphocytic infiltration and histological grade were not found to be significant by related to the local recurrence and survival (P>0.05).

CONCLUSION

Local tumor excision was a safe procedure for the treatment of early stage low rectal carcinoma with minimal morbidity and mortality, which might serves as one of the primary surgical treatment methods for the disease of this kind.

Arterial chemotherapy of 5-fluorouracil and mitomycin C in the treatment of liver metastases of colorectal cancer

AIM: Regional chemotherapy using hepatic artery catheters is a good method of treating patients with colorectal cancer liver metastases. We investigated the survival of patients with liver metastases from colorectal cancer using 5-fluorouracil (5-FU) and mitomycin C Cthrough implantable hepatic arterial infusion port.

METHODS: Seventy-five patients with inoperable liver metastases from colorectal cancer were included between March, 1992 and November, 2001. We placed implantable hepatic arterial catheter (HAC) port by laparotomy.5-FU, 1000 mg/m²/d continuous infusion for five days every four weeks, was delivered in the hepatic arterial catheter through the port. Mitomycin C, 30 mg/m²/d infusion in the first day every cycle through the port. Response to the treatment was evaluated by serial determinations of plasma CEA and imaging techniques consisting of computerized tomography and sonography of liver.

RESULTS: Sixty-eight were performed hepatic artery chemotherapy and fifty-six were followed up among seventy-five HAC patients. Twenty-six patients (46.4%) have responded and 4 complete remission were achieved. Eight patients (14.3%) had stable liver metastases. Twenty-two patients (39.3%) were progressed with increased tumor size and number. Twenty-nine patients (51.8%) had a decreased serum CEA level, while 10 patients (17.9%) were stable and 17 patients (30.4%) had an increased serum CEA level. There were no operative death in this series. Complications, which occurred in 18 patients (32.1%), were as followed: hepatic artery thrombosis in 11, Upper gastric and intestinal bleeding in 3, liver abscess in 1, pocket infection in 1, cholangitis in 1, and hepatic artery pseudo-aneurysm in one patient.

CONCLUSION: Combined infusion of 5-FU and mitomycin C by hepatic artery catheter port is an effective treatment for liver metastases from colorectal cancer. The high response and lower complication rates prove the adjuvant treatment of colorectal cancer with this treatment.