Robotic right versus left colectomy for colorectal neoplasia: a systemic review and meta-analysis

Previous studies comparing right and left colectomies have shown variable short-term outcomes. Despite the rapid adoption of robotics in colorectal operations, few studies have addressed outcome differences between robotic right (RRC) and left (RLC) colectomies. Therefore, we sought to compare the short-term outcomes of RRC and RLC for neoplasia. This is a systematic review and meta-analysis of articles published from the time of inception of the datasets to May 1, 2022. The electronic databases included English publications in Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, and Scopus. A total of 13,514 patients with colon neoplasia enrolled in 9 comparative studies were included. The overall mean age was 64.1 years (standard deviation [SD] ± 9.8), and there was a minor female predominance (52% female vs. 48% male). 8656 (64.0%) underwent RRC and 4858 (36.0%) underwent RLC. The ASA score 1 of - 2 in the LRC group was 37% vs. 21% in the R. Whereas the ASA score 3-4 was 62% in the LRC vs. 76% in RRC. Moreover, the mean of the Charlson Comorbidity Score in the LRC was 4.3 (SD 1.9) vs. 3.1 (SD 2.3) in the RRC. Meta-analysis revealed a significantly higher rate of ileus in RRC (10%) compared to RLC (7%) (OR 1.46, 95% CI 1.27-1.67). Additionally, operative time was significantly shorter by 22.6 min in RRC versus LRC (95% CI - 37.4-7.8; p < 0.001). There were no statistically significant differences between RRC and RLC in conversion to open operation, estimated blood loss, wound infection, anastomotic leak, reoperation, readmission, and hospital length of stay. In this only meta-analysis comparing RRC and LRC for colon neoplasia, we found that RRC was independently associated with a shorter operative time but increased risk of ileus.

Effectiveness of Multiple Consecutive Fecal Immunohistochemical Testing for Colorectal Cancer Screening

OBJECTIVE

The fecal immunohistochemical test (FIT) is a simple colorectal-cancer screening test. There are no recent studies evaluating the benefits of doing more than one a year. Our study aimed to evaluate the effectiveness of performing the test for 3 consecutive days in terms of detecting cancer and advanced adenomas.

METHODS

This was a single-center retrospective review of records of patients who had daily tests for 3 consecutive days and had at least one positive during the period from 2009-2011.

RESULTS

A total of 456 records were reviewed, 410 met the inclusion criteria. Most of the participants were men (95.9%), with the mean age of all the participants being 64.3 (±7.8) years. Regarding the FIT results, 18.8% had positive results on all 3 tests, 20.2% had 2 positive tests, and 61.0% had 1 positive FIT. There were 16 (3.9%) patients in the studied sample that had colon cancer. Their lesions were located predominantly in the distal colon (ratio of distal to proximal: 2:1). The patients with 3 positive FITs had a higher prevalence of advanced adenomas (33.3% vs. 13.4%, respectively; P < .05).

DISCUSSION

Our study showed a low concordance between daily consecutive tests results. those patients with more than 1 positive FIT had a higher prevalence of advanced adenoma or adenocarcinoma than patients who had only one. Fewer than 4% of the patients in our study had colon cancer. Prospective studies would be needed to determine the effectiveness of more than 1 annual FIT in colon cancer prevention.

Comment on “Artificial intelligence in gastroenterology: A state-of-the-art review”

Colon capsule endoscopy (CCE) was introduced nearly two decades ago. Initially, it was limited by poor image quality and short battery time, but due to technical improvements, it has become an equal diagnostic alternative to optical colonoscopy (OC). Hastened by the coronavirus disease 2019 pandemic, CCE has been introduced in clinical practice to relieve overburdened endoscopy units and move investigations to out-patient clinics. A wider adoption of CCE would be bolstered by positive patient experience, as it offers a diagnostic investigation that is not inferior to other modalities. The shortcomings of CCE include its inability to differentiate adenomatous polyps from hyperplastic polyps. Solving this issue would improve the stratification of patients for polyp removal. Artificial intelligence (AI) has shown promising results in polyp detection and characterization to minimize incomplete CCEs and avoid needless examinations. Onboard AI appears to be a needed application to enable near-real-time decision-making in order to diminish patient waiting times and avoid superfluous subsequent OCs. With this letter, we discuss the potential and role of AI in CCE as a diagnostic tool for the large bowel.

Impact of physical activity and diet on colorectal cancer survivors' quality of life: a systematic review

Background

Post-treatment management is essential for improving the health and quality of life of colorectal cancer (CRC) survivors. The number of cancer survivors is continually increasing, which is causing a corresponding growth in the need for effective post-treatment management programs. Current research on the topic indicates that such programs should include aspects such as physical activity and a proper diet, which would form the basis of lifestyle change among CRC survivors. Therefore, this study aimed to identify the impact of physical activity and diet on the quality of life of CRC survivors.

Methods

We performed a systematic literature review regarding CRC survivors. We searched the Embase, PubMed, and EBSCOhost databases, considering papers published between January 2000 and May 2017 in any language, using a combination of the following subject headings: “colorectal cancer,” “colorectal carcinoma survivor,” “survivorship plan,” “survivorship care plan,” “survivorship program,” “lifestyle,” “activities,” “exercise,” “diet program,” and “nutrition.”

Results

A total of 14,036 articles were identified, with 35 satisfying the eligibility criteria for the systematic review. These articles were grouped by the study questions into physical activity and diet: 24 articles were included in the physical activity group and 11 in the diet group.

Conclusions

The research showed that an effective survivorship program can significantly help CRC survivors maintain good health and quality of life for long periods. However, there is a lack of consensus and conclusive evidence regarding how the guidelines for such a program should be designed, in terms of both its form and content.

Comparison of Clinical Outcomes Between Laparoscopic-Assisted and Minilaparotomy Approaches for Colon Cancer

BACKGROUND/AIMS

The minilaparotomy approach is feasible for the resection of colon cancer. This study aimed to compare the clinical and oncological outcomes of minilaparotomy and laparoscopic approaches in patients with colon cancer.

METHODS

We performed a retrospective analysis of consecutive patients undergoing minilaparotomy or laparoscopic resection for colon cancer from January 2009 to December 2014.

RESULTS

There were 376 patients with colon cancer. Seventy-one patients were excluded. The remaining 305 patients were allocated to the minilaparotomy (n = 146) group or laparoscopic group (n = 159). The demographic data of the two groups was similar except for body mass index. The time to first bowel movement (P = 0.000) and the hospital stay (P = 0.005) were less in the laparoscopic group. Compared with the minilaparotomy group, the mean operation time was longer and the costs higher for laparoscopic group (P = 0.000). The morbidity, mortality, and local recurrence were comparable between the two groups. The 5-year overall and disease-free survival rates were also similar (overall survival is 75.3 vs. 72.9%, P = 0.648; disease-free survival is 66.2 vs. 70.2%, P = 0.914).

CONCLUSION

The minilaparotomy approach was safe and equivalent to laparoscopic approach for patients with colon cancer. It is an alternative to the laparoscopic approach in selected patients.

Prognostic value of inferior mesenteric artery lymph node metastasis in cancer of the descending colon, sigmoid colon and rectum

AIM

This study aimed to analyse the potential significance of metastasis to the inferior mesenteric artery lymph node (IMA-LN) in patients with malignancy of the left colon and rectum.

METHOD

A retrospective analysis of a cohort of 890 patients collected prospectively who underwent radical resection of a primary tumour of the descending colon, sigmoid colon and rectum in our department from 1 January 2009 to 31 December 2015 was performed. Patients were divided into an IMA-LN metastasis (IMA-LN (+)) group (n = 51) and a non IMA-LN metastasis (IMA-LN (-)) group (n = 839). A total of 801 patients were followed by a designated member of the study staff. Clinical features, pathological characteristics, recurrence patterns and survival rates were compared between the two groups.

RESULTS

In the IMA-LN (+) group, the risk ratio of overall recurrence and tumour related death was 7.786 (95% CI 4.142-14.637) and 7.756 (95% CI 4.142-14.525) respectively. Significant differences were found in overall survival (log-rank: χ²  = 69.06, P < 0.0001) and disease-free survival (log-rank: χ²  = 69.06, P < 0.0001) between the two groups. Furthermore, there were significant differences in overall survival (log-rank: χ²  = 18.47, P < 0.0001) and disease-free survival (log-rank: χ²  = 16.99, P < 0.0001) between the IMA-LN (-) and IMA-LN (+) subgroups of patients with Stage N2 disease. Multivariate survival analysis indicated that IMA-LN (+) was an independent risk factor of poor prognosis. There was no difference in the prognosis between high tie and low tie with IMA-LN dissection.

CONCLUSION

Inferior mesenteric artery lymph node metastasis was an independent predictive factor for high systemic recurrence. Low ligation of the IMA with IMA-LN dissection was not inferior to high ligation.

Adenoma Detection Rate in Asymptomatic Patients with Positive Fecal Immunochemical Tests

BACKGROUND AND AIMS

The adenoma detection rate (ADR) is a powerful measure of screening colonoscopy quality. Patients who undergo colonoscopy for the evaluation of a positive fecal immunochemical test (FIT) have increased prevalence of colorectal neoplasia, but it is not known whether separate quality benchmarks are required. The aim of this study was to compare the conventional ADR to the ADR of colonoscopies performed for the evaluation of positive FIT, in asymptomatic average-risk patients.

METHODS

Patients ≥ 50 years old who underwent colonoscopy for the evaluation of a positive FIT between January 1, 2013, and July 31, 2014, at a tertiary Veterans Affairs Medical Center were identified. FIT performed for any indication other than average-risk screening was excluded. The comparison group included average-risk patients ≥ 50 years old undergoing screening colonoscopy during the same time frame. The two groups were compared for ADR, advanced neoplasm [adenoma ≥ 10 mm, tubulovillous, high-grade dysplasia, CRC, sessile serrated polyp (SSP) ≥ 10 mm], CRC, and SSP detection after propensity score adjustment using a logistic regression model adjusted for endoscopist.

RESULTS

There were 207 patients in the FIT group and 601 in the screening colonoscopy comparison group. After propensity score adjustment, ADR (72.9 vs. 50.0%, p = 0.003), number of adenomas per colonoscopy (3.3 ± 3.6 vs. 1.4 ± 2.3, p = 0.033), and advanced neoplasm detection rate (32.4 vs. 11.0%, p < 0.0001) were significantly higher in the FIT group. There were no significant differences in the number of CRC and the SSP detection rate.

CONCLUSIONS

In this cohort of average-risk Veterans, the ADR of colonoscopies performed for the evaluation of a positive FIT was higher than the ADR of screening colonoscopies. Patients with a positive FIT also had significantly more adenomas per colonoscopy and advanced neoplasms. These findings suggest that the quality of colonoscopies performed for a positive FIT is insufficiently assessed by the conventional ADR and requires additional quality metrics.

Synchronous quintuple primary gastrointestinal tract malignancies: Case report

Multiple primary malignancy is defined as two or more malignancies detected in an individual person. In particular, synchronous quintuple primary malignancy is extremely rare. A 52-year-old male with anal pain and intermittent blood-tinged stool was diagnosed with malignancies in the stomach, jejunum, ascending colon, transverse colon and rectum. He underwent a subtotal gastrectomy, segmental resection of the jejunum and total protocolectomy with end ileostomy. The postoperative pathologic findings were moderate differentiated gastric adenocarcinoma (pT1bN0M0, pStageIA), combined adenocarcinoma and neuroendocrine carcinoma of the jejunum (pT3N0M0, pStageIIA), three mucinous adenocarcinoma of the ascending colon (pT3N0M0, pStageIIA), transverse colon (pT1N0M0, pStageI) and rectum (pT3N1aM0, pStageIIIB). The tumors did not lack MLH-1 and MSH-2 expression, as the markers (bat26, D5S346, bat25, D2S123) suggest MSI-H presence. Adjuvant chemoradiotherapy was started according to regimen, FOLFOX 4 for advanced rectal cancer. Six years post-operation, the patient is currently attending regular follow-ups without recurrence or metastasis.

Efficacy and adverse events of cold vs hot polypectomy: A meta-analysis

AIM: To compare previously reported randomized controlled studies (RCTs) of cold and hot polypectomy, we systematically reviewed and clarify the utility of cold polypectomy over hot with respect to efficacy and adverse events.

METHODS: A meta-analysis was conducted to evaluate the predominance of cold and hot polypectomy for removing colon polyps. Published articles and abstracts from worldwide conferences were searched using the keywords “cold polypectomy”. RCTs that compared either or both the effects or adverse events of cold polypectomy with those of hot polypectomy were collected. The patients’ demographics, endoscopic procedures, No. of examined lesions, lesion size, macroscopic and histologic findings, rates of incomplete resection, bleeding amount, perforation, and length of procedure were extracted from each study. A forest plot analysis was used to verify the relative strength of the effects and adverse events of each procedure. A funnel plot was generated to assess the possibility of publication bias.

RESULTS: Ultimately, six RCTs were selected. No significant differences were noted in the average lesion size (less than 10 mm) between the cold and hot polypectomy groups in each study. Further, the rates of complete resection and adverse events, including delayed bleeding, did not differ markedly between cold and hot polypectomy. The average procedural time in the cold polypectomy group was significantly shorter than in the hot polypectomy group.

CONCLUSION: Cold polypectomy is a time-saving procedure for removing small polyps with markedly similar curability and safety to hot polypectomy.

Positive MACC1 expression correlates with invasive behaviors and postoperative liver metastasis in colon cancer

OBJECTIVE

Metastasis-associated in colon cancer-1 (MACC1), a new gene associated with primary and metastatic colon cancer, promotes tumor cell growth as well as the development of distant metastasis. The aim of this study is to investigate the expression of MACC1 protein in colon cancer and its association with clinicopathological parameters and postoperative liver metastasis.

MATERIALS AND METHODS

Expression of MACC1 protein was detected immunohistochemically in paraffin-embedded specimens of 96 cases of colon cancer. Relationship between MACC1 protein expression and clinicopathological parameters, postoperative liver metastasis were analyzed.

RESULTS

Immunohistochemistry examination showed that MACC1 protein expression was significantly more abundant in colon cancer tissues than in normal colon tissues (P = 0.038), Positive rate of MACC1 expression in colon cancer tissues was increased significantly in patients with lymph node metastases (P = 0.001) and higher T stages (P = 0.006). Postoperative live metastasis-free survival period was significantly longer in negative MACC1 expression group than that of positive MACC1 expression group (36.4 ± 2.85 vs. 28.6 ± 2.02 months, P = 0.014). Multivariate analysis showed that MACC1 expression level is an independent prognostic factor for postoperative live metastasis-free survival (95% confidence interval [CI] =1.32-3.38, P = 0.006).

CONCLUSIONS

Our results suggest that MACC1 expression level might play an important role in colon cancer invasion and MACC1 expression level is an independent biomarker for postoperative liver metastasis in patients with colon cancer.

Laterally spreading tumors: Limitations of computed tomography colonography

AIM: To prospectively investigate the detection rate of laterally spreading tumors (LSTs) of the colorectum by computed tomography (CT) colonography (CTC).

METHODS: Patients with LSTs measuring ≥ 20 mm detected during colonoscopy were prospectively enrolled in the study. All patients underwent colonoscopy and subsequent CTC on the same day. CTC was performed using multi-detector CT without contrast in the prone and supine positions. Two radiologists blinded to the existence of LSTs read the virtual endoscopic images as well as 2-D images. LSTs were classified into granular and non-granular types based on colonoscopic appearance.

RESULTS: Forty-seven pathologically proven LSTs were evaluated prospectively. Histology included adenomas in 19, mucosal cancers in 19 and T1 cancers in 9. The mean diameter of the LSTs was 35.1 mm. Twenty-eight (60%) LSTs were correctly identified by CTC, and the configuration was similar to the colonoscopic appearance in most cases. Detection rate for the granular type was significantly higher than that for the non-granular type (71% vs 31%, P = 0.013). Detection rate of adenomas was significantly lower than mucosal cancers (32% vs 79%, P = 0.008) and T1 cancers (32% vs 78%, P = 0.042).

CONCLUSION: The detection rate of LSTs by CTC, particularly the non-granular type was not acceptable. Practitioners should be aware of the relatively low detection rate when using CTC.

Laparoscopic segmental colectomy for colonic lymphangiomas: A definitive, minimally invasive surgical option

Colonic lymphangioma is an unusual benign malformation. We herein describe two cases. A 36-year-old woman was admitted with one year of intermittent abdominal pain; colonoscopy, abdominopelvic computed tomography and endoscopic ultrasonography (EUS) revealed enlarged cystic masses at the ascending colon. In another 40-year-old man, colonoscopy and EUS revealed an asymptomatic lobulated cystic mass with four small sessile polyps at the sigmoid colon. Both patients underwent laparoscopic segmental colectomy. Both masses were histologically confirmed as cystic lymphangiomas, and the patients were discharged without complications. The management of colonic lymphangioma depends on the individual situation; close surveillance or endoscopic therapy may be appropriate for asymptomatic lesions smaller than 2.5 cm in diameter. Surgical intervention can be considered for larger lesions or in patients who develop complication risks. Laparoscopic segmental colon resection may be recommended to excise relatively large submucosal lesions because it is a definitive, minimally invasive intervention with a fast postoperative recovery.

Oncologic Outcomes of Stage IIIA Colon Cancer for Different Chemotherapeutic Regimens

Purpose

Adjuvant chemotherapy is currently recommended for Stage IIIA colon cancers. This study aimed to elucidate the oncologic outcomes of Stage IIIA colon cancer according to the chemotherapeutic regimen based on a retrospective review.

Methods

From 1995 to 2008, Stage IIIA colon cancer patients were identified from a prospectively maintained database at a single institution. Exclusion criteria were as follows: rectal cancer, another malignancy other than colon cancer, no adjuvant chemotherapy and unknown chemotherapeutic regimen. One hundred thirty-one patients were enrolled in the study, and the clinicopathologic and the oncologic characteristics were analyzed. The number of males was 72, and the number of females was 59; the mean age was 59.5 years (range, 25 to 76 years), and the median follow-up period was 33 months (range, 2 to 127 months).

Results

Of the 131 patients, fluorouracil/leucovorin (FL)/capecitabine chemotherapy was performed in 109 patients, and FOLFOX chemotherapy was performed in 22 patients. When the patients who received FL/capecitabine chemotherapy and the patients who received FOLFOX chemotherapy were compared, there was no significant difference in the clinicopathologic factors between the two groups. The 5-year overall survival and the 5-year disease-free survival were 97.2% and 94.5% in the FL/capecitabine patient group and 95.5% and 90.9% in the FOLFOX patient group, respectively, and no statistically significant differences were noted between the two groups.

Conclusion

Stage IIIA colon cancer showed good oncologic outcomes, and the chemotherapeutic regimen did not seem to affect the oncologic outcome.

Expression of glioma-associated oncogene homolog 1 is associated with invasion and postoperative liver metastasis in colon cancer

OBJECTIVE

To investigate the expression of glioma-associated oncogene homolog 1(Gli-1) in colon cancer and its association with clinicopathological parameters and postoperative liver metastasis.

METHODS

Expression of Gli-1 was detected by immunohistochemistry in paraffin-embedded specimens of 96 cases of colon cancer. Relationship between Gli-1 expression and clinicopathological parameters, postoperative liver metastasis were analyzed.

RESULTS

Gli-1 protein expression was significantly increased in colon cancer tissues compared to normal colon tissues (P=0.037). Gli-1 expression in colon tissues was increased in patients with lymph node metastases (P=0.022) and higher T stages (P=0.030). Postoperative live metastasis-free survival period was significantly longer in low Gli-1 expression group than that of high Gli-1 expression group (48.22±10.03 months vs 20.46±6.32 months, P=0.001). Multivariate analysis showed that Gli-1 expression level is an independent prognostic factor for postoperative live metastasis-free survival.

CONCLUSION

Colon cancer is associated with an upregulation of Gli-1 protein expression in colon tissues. In patients with colon cancer, Gli-1 expression level is closely related to lymph node metastases, T stages and postoperative live metastasis-free survival periods, indicative of a possible role of Gli-1 expression in colon cancer progression.

Compliance and effective management of the hand-foot syndrome in colon cancer patients receiving capecitabine as adjuvant chemotherapy

PURPOSE

Physicians and oncology nurses must continue to update their knowledge on treatment and treatment-related side effects, while searching for effective methods to prevent or manage side effects. The objective of our study was to describe the incidence and response to treatment of the hand-foot syndrome (HFS) and the compliance with treatment of patients with stage IIB, IIIA, IIIB, and IIIC colon cancer that were treated with capecitabine alone as adjuvant therapy.

MATERIALS AND METHODS

Between September 2005 and September 2006, 84 patients fulfilled the inclusion criteria and were included in this retrospective analysis of prospectively collected data.

RESULTS

The treatment compliance rate was 90.5% (76 out of the 84 patients). The HFS developed in 65 patients (77.4%). Thirty-three patients (50.7%) had grade 1 HFS, 22 patients (33.8%) had grade 2 HFS and 10 patients (15.5%) had grade 3 HFS, as their most severe episode. For Grade 1 patients, the dose was maintained, and skin barrier cream and moist exposed burn ointment (MEBO) were applied. For Grade 2 patients, either the dose was maintained or 25% of the dose was reduced; MEBO and supportive care were provided. For Grade 3 patients, one cycle of chemotherapy was interrupted followed by dose adjustment; MEBO and supportive care were provided.

CONCLUSION

HFS is manageable if both patients and oncology care teams are educated about HFS associated with capecitabine. The HFS is treated by patient education, preventive management, ointment application, conservative management, dose reduction, and interruption of chemotherapy administration.

Ascending colon adenocarcinoma with tonsillar metastasis: A case report and review of the literature

Metastatic palatine tonsil cancer is extremely rare, with nearly 100 such tumors reported in the English literature. The prognosis of metastatic palatine tonsil cancer is poor. A 53-year-old man presented with painless left palatine tonsillar swelling and a cervical mass following right hemicolectomy for an ascending colon adenocarcinoma. Physical examination showed an ulcerated mass located on the upper pole of the left palatine tonsil. A punch biopsy was taken for histological examination which showed a moderately-differentiated adenocarcinoma. The patient was treated with palliative radiotherapy and chemotherapy. He was still alive when we wrote this paper. Our case shows that immunohistochemical diagnosis of metastatic palatine tonsil cancer is essential.

Differences in characteristics of colorectal neoplasm between young and elderly Thais

AIM: To analyze the differences of clinical characteristics of colorectal neoplasm including polyps between the elderly and young Thai patients.

METHODS: Colonoscopy database from December 2000 to October 2004 was retrospectively analyzed. There were 1822 eligible patients who underwent colonoscopy (with a mean age of 56.6 years). Patients were classified into two groups: the older age group (aged ≥ 60 years; n = 989) and the younger age group (aged < 60 years; n = 833). Data were recorded on age, colonoscopic indications, tumor location, colonoscopic findings and their related histological findings.

RESULTS: Colorectal malignancy related lesions were more often found in the older age group (21%) than in the younger age group (12%). Left-sided lesions were detected more commonly than right-sided in both age groups in approximately two-thirds of all cases. Hematochezia showed greater association with left-sided lesions in the elderly. No relationship was found between age and neoplasm staging and severity.

CONCLUSION: The chance of detecting colorectal neoplasm by colonoscopy was higher in the elderly than in the young Thais. However, both groups had the lesions predominantly located in the left side.

Mechanism of counterattack of colorectal cancer cell by Fas/Fas ligand system

AIM: To determine the role of Fas/Fas ligand (FasL) in the immune escape of colon cancer cells.

METHODS: Immunohistochemistry was used to observe the expression of Fas and FasL in the tissues of colon cancer patients.In situ hybridization was used to detect the localization of FasL mRNA expression in cancer tissues. Terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay and CD45 staining were performed to detect the apoptosis of tumor-infiltrating lymphocytes (TILs). Co-culture assays of colon cancer cells (SW480) and Jurkat cells (Fas-sensitive cells) were performed to observe the counterattack of colon cancer cells to lymphocytes.

RESULTS: Of 53 cases of colon carcinomas, 23 cases (43.4%) expressed Fas which was significantly lower as compared to the normal colonic mucosa (73.3%, P<0.01), and 45 cases (84.9%) of colon carcinomas expressed FasL, whereas only two cases (3.75%) in normal mucosa expressed FasL. FasL expression in the colon cancer cells was found to be associated with increased cell death of TILs. The apoptotic rate of TIL in the FasL-positive staining regions of tumor cells was significantly higher than that in the FasL-negative staining region (54.84 ± 2.79% vs 25.73 ± 1.98%, P<0.01). The co-culture of SW480 cells and Jurkat cells confirmed the function of FasL on the SW480 cells. The apoptotic rates of Jurkat cells were found to be related with the amount of SW480 cells.

CONCLUSION: Colon cancer cells can escape the immune surveillance and killing via decreasing Fas expression, and can counterattack the immune system via increasing FasL expression. Fas/FasL can serve as potential targets for effective antitumor therapy.

Molecular epidemiology of colon cancer

Colorectal cancer appears to have rapidly increased over the past two decades in Korea. Environmental factors, characterized by a western life style, seem to be closely related to the increased risk of colorectal cancer. Higher intakes of meat, a lower vegetable intake, a lack of physical activity, obesity, and alcohol drinking have been suggested to be risk factors for colorectal cancer in the numerous epidemiologic studies. Several specific associations have also been observed between genetic polymorphisms and colorectal cancer. Moreover, it has been postulated that environmental factors and a genetic predisposition work in concert in colorectal cancer development. A stronger association between red meat intake and colorectal cancer among those with rapid acetylators at either the NAT1 or NAT2 locus was reported, particularly for colorectal cancer associated with K-ras mutations. The protective effect of the homozygous variant TT form of the MTHFR genotype on the risk of colon cancer seems to be modified by the level of methyl diets, i.e., by folate, which has a protective effect, or conversely by alcohol. The insulin-related pathway, which possibly explains at a mechanistic level the effect of physical activity and obesity on colon cancer, appears to be a common denominator in colon cancer and in other metabolic disorders, such as diabetes mellitus and dyslipidemia. Hyperinsulinemia has been proposed as an explanation for the association between a Western lifestyle and colon cancer risk. Further studies, that incorporate both genetic and environmental factors, are needed to fully explain and identify the underlying pathway of colorectal carcinogenesis.