Colorectal polyp outcomes after participation in the seAFOod polyp prevention trial: Evidence of rebound elevated colorectal polyp risk after short-term aspirin use

BACKGROUND

The seAFOod polyp prevention trial was a randomised, placebo-controlled, 2 × 2 factorial trial of aspirin 300 mg and eicosapentaenoic acid (EPA) 2000 mg daily in individuals who had a screening colonoscopy in the English Bowel Cancer Screening Programme (BCSP). Aspirin treatment was associated with a 20% reduction in colorectal polyp number at BCSP surveillance colonoscopy 12 months later. It is unclear what happens to colorectal polyp risk after short-term aspirin use.

AIM

To investigate colorectal polyp risk according to the original trial treatment allocation, up to 6 years after trial participation.

METHODS

All seAFOod trial participants were scheduled for further BCSP surveillance and provided informed consent for the collection of colonoscopy outcomes. We linked BCSP colonoscopy data to trial outcomes data.

RESULTS

In total, 507 individuals underwent one or more colonoscopies after trial participation. Individuals grouped by treatment allocation were well matched for clinical characteristics, follow-up duration and number of surveillance colonoscopies. The polyp detection rate (PDR; the number of individuals who had ≥1 colorectal polyp detected) after randomization to placebo aspirin was 71.1%. The PDR was 80.1% for individuals who had received aspirin (odds ratio [OR] 1.13 [95% confidence interval 1.02, 1.24]; p = 0.02). There was no difference in colorectal polyp outcomes between individuals who had been allocated to EPA compared with its placebo (OR for PDR 1.00 [0.91, 1.10]; p = 0.92).

CONCLUSION

Individuals who received aspirin in the seAFOod trial demonstrated increased colorectal polyp risk during post-trial surveillance. Rebound elevated neoplastic risk after short-term aspirin use has important implications for aspirin cessation driven by age-related bleeding risk. ISRCTN05926847.

The Cytotoxic Effect of Isolated Cannabinoid Extracts on Polypoid Colorectal Tissue

Purified cannabinoids have been shown to prevent proliferation and induce apoptosis in colorectal carcinoma cell lines. To assess the cytotoxic effect of cannabinoid extracts and purified cannabinoids on both colorectal polyps and normal colonic cells, as well as their synergistic interaction. Various blends were tested to identify the optimal synergistic effect. Methods: Biopsies from polyps and healthy colonic tissue were obtained from 22 patients undergoing colonic polypectomies. The toxicity of a variety of cannabinoid extracts and purified cannabinoids at different concentrations was evaluated. The synergistic effect of cannabinoids was calculated based on the cells’ survival. Isolated cannabinoids illustrated different toxic effects on the viability of cells derived from colorectal polyps. THC-d8 and THC-d9 were the most toxic and exhibited persistent toxicity in all the polyps tested. CBD was more toxic to polypoid cells in comparison to normal colonic cells at a concentration of 15 µM. The combinations of the cannabinoids CBDV, THCV, CBDVA, CBCA, and CBGA exhibited a synergistic inhibitory effect on the viability of cells derived from colon polyps of patients. Isolated cannabinoid compounds interacted synergistically against colonic polyps, and some also possessed a differential toxic effect on polyp and adjacent colonic tissue, suggesting possible future therapeutic value.

The efficacy and safety of sulindac for colorectal polyps: A protocol for systematic review and meta-analysis

BACKGROUND

Sulindac has been used for treating colorectal polyps widely. However, the efficacy and safety of sulindac for colorectal polyps are unclear. This study aims to evaluate the efficacy and safety of sulindac for colorectal polyps.

METHODS

Randomized controlled trials of sulindac in the treatment of colorectal polyps will be searched in PubMed, EMbase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), WanFang, the Chongqing VIP Chinese Science, and Technology Periodical Database, and China biomedical literature database (CBM) from inception to August, 2020. And Baidu Scholar, Google Scholar, International Clinical Trials Registry Platform, and Chinese Clinical Trials Registry will be searched to obtain more relevant studies comprehensively. Two researchers will perform data extraction and risk of bias assessment independently. Statistical analysis will be conducted in RevMan 5.3.

RESULTS

This study will summarize the present evidence by exploring the efficacy and safety of sulindac in the treatment of colorectal polyps.

CONCLUSION

The findings of the study will provide helpful evidence for the efficacy and safety of sulindac in the treatment of colorectal polyps, facilitating clinical practice and further scientific studies.

ETHICS AND DISSEMINATION

The private information from individuals will not publish. This systematic review also will not involve endangering participant rights. Ethical approval is not required. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/N5GDH.

Safety of Cold Snare Polypectomy in Patients Receiving Treatment with Antithrombotic Agents

BACKGROUND

With the aging of the population and rising incidence of thromboembolic events, the clinical use of antithrombotic agents is also increasing. There are few reports yet on the management of antithrombotic agent use in patients undergoing cold snare polypectomy (CSP).

AIMS

The aim of this study was to evaluate whether continued administration of antithrombotic agents in patients undergoing CSP would be associated with an increased rate of delayed post-polypectomy bleeding (DPPB).

METHODS

A total of 1177 colorectal polyps in 501 patients were resected at Omori Red Cross Hospital between October 2017 and March 2018. The polyps were divided into two groups depending on whether the patients received antithrombotic agent treatment or not: the antithrombotic group (911 polyps) and the no-antithrombotic group (266 polyps).

RESULTS

Among the 1177 polyp resections, there was no case of DPPB, including in the antithrombotic group. Immediate bleeding occurred in a total of 63 (5.4%) cases. Polyp location in the rectum (OR (95% CI) 2.64 (1.223-5.679); p = 0.013), polyp size ≥ 6 mm (OR (95% CI) 4.64 (2.719-7.933); p < 0.001), polypoid growth pattern (OR (95% CI) 2.78 (1.607-4.793); p < 0.001), and antithrombotic agent use (OR (95% CI) 2.98 (1.715-5.183); p < 0.001) were identified as significant risk factors of immediate bleeding.

CONCLUSIONS

Continued use of antithrombotic agents does not increase the risk of DPPB, even in those receiving multiple antithrombotic agents. Thus, it is safe to perform CSP even in multiple agent users. Prospective, randomized studies are necessary to confirm our results.

Normalization of the microbiota in patients after treatment for colonic lesions

BACKGROUND

Colorectal cancer is a worldwide health problem. Despite growing evidence that members of the gut microbiota can drive tumorigenesis, little is known about what happens to it after treatment for an adenoma or carcinoma. This study tested the hypothesis that treatment for adenoma or carcinoma alters the abundance of bacterial populations associated with disease to those associated with a normal colon. We tested this hypothesis by sequencing the 16S rRNA genes in the feces of 67 individuals before and after treatment for adenoma (N = 22), advanced adenoma (N = 19), and carcinoma (N = 26).

RESULTS

There were small changes to the bacterial community associated with adenoma or advanced adenoma and large changes associated with carcinoma. The communities from patients with carcinomas changed significantly more than those with adenoma following treatment (P value < 0.001). Although treatment was associated with intrapersonal changes, the change in the abundance of individual OTUs in response to treatment was not consistent within diagnosis groups (P value > 0.05). Because the distribution of OTUs across patients and diagnosis groups was irregular, we used the random forest machine learning algorithm to identify groups of OTUs that could be used to classify pre and post-treatment samples for each of the diagnosis groups. Although the adenoma and carcinoma models could reliably differentiate between the pre- and post-treatment samples (P value < 0.001), the advanced-adenoma model could not (P value = 0.61). Furthermore, there was little overlap between the OTUs that were indicative of each treatment. To determine whether individuals who underwent treatment were more likely to have OTUs associated with normal colons we used a larger cohort that contained individuals with normal colons and those with adenomas, advanced adenomas, and carcinomas. We again built random forest models and measured the change in the positive probability of having one of the three diagnoses to assess whether the post-treatment samples received the same classification as the pre-treatment samples. Samples from patients who had carcinomas changed toward a microbial milieu that resembles the normal colon after treatment (P value < 0.001). Finally, we were unable to detect any significant differences in the microbiota of individuals treated with surgery alone and those treated with chemotherapy or chemotherapy and radiation (P value > 0.05).

CONCLUSIONS

By better understanding the response of the microbiota to treatment for adenomas and carcinomas, it is likely that biomarkers will eventually be validated that can be used to quantify the risk of recurrence and the likelihood of survival. Although it was difficult to identify significant differences between pre- and post-treatment samples from patients with adenoma and advanced adenoma, this was not the case for carcinomas. Not only were there large changes in pre- versus post-treatment samples for those with carcinoma, but also these changes were toward a more normal microbiota.

Estrogen receptor beta as target for colorectal cancer prevention

Colorectal cancer (CRC) is a leading cause of death in the United States. Despite its slow development and the capacity for early diagnosis, current preventive approaches are not sufficient. However, a role for estrogen has been demonstrated in multiple epidemiologic studies, which may benefit CRC prevention. A large body of evidence from preclinical studies indicates that expression of the estrogen receptor beta (ERβ/ESR2) demonstrates an inverse relationship with the presence of colorectal polyps and stage of tumors, and can mediate a protective response. Natural compounds, including phytoestrogens, or synthetic ERβ selective agonists, can activate or upregulate ERβ in the colon and promote apoptosis in preclinical models and in clinical experience. Importantly, this activity has been associated with a reduction in polyp formation and, in rodent models of CRC, has been shown to lower incidence of colon adenocarcinoma. Collectively, these findings indicate that targeted activation of ERβ may represent a novel clinical approach for management of colorectal adenomatous polyps and prevention of colorectal carcinoma in patients at risk for this condition. In this review, we discuss the potential of new chemopreventive or dietary approaches based on estrogen signaling.

A multimineral natural product from red marine algae reduces colon polyp formation in C57BL/6 mice

The goal of this study was to determine if a multimineral natural product derived from red marine algae could reduce colon polyp formation in mice on a high-fat diet. C57BL/6 mice were maintained for up to 18 mo either on a high-fat "Western-style" diet or on a low-fat diet (AIN 76A), with or without the multimineral-supplement. To summarize, colon polyps were detected in 22 of 70 mice (31%) on the high-fat diet but in only 2 of 70 mice (3%) receiving the mineral-supplemented high-fat diet (P < 0.0001). Colon polyps were detected in 16 of 70 mice (23%) in the low-fat group; not significantly different from high-fat group but significantly higher than the high-fat-supplemented group (P = 0.0006). This was in spite of the fact that the calcium level in the low-fat diet was comparable to the level of calcium in the high-fat diet containing the multimineral-product. Supplementation of the low-fat diet reduced the incidence to 8 of 70 mice (11% incidence). Taken together, these findings demonstrate that a multimineral natural product can protect mice on a high-fat diet against adenomatous polyp formation in the colon. These data suggest that increased calcium alone is insufficient to explain the lower incidence of colon polyps.

Eicosapentaenoic acid (EPA) efficacy for colorectal aberrant crypt foci (ACF): a double-blind randomized controlled trial

BACKGROUND

Colorectal cancer (CRC) is one of the most commonly occurring neoplasms and a leading cause of cancer death worldwide, and new preventive strategies are needed to lower the burden of this disease. Eicosapentaenoic acid (EPA), the omega-3 polyunsaturated fatty acid that is widely used in the treatment of hyperlipidemia and prevention of cardiovascular disease, has recently been suggested to have a suppressive effect on tumorigenesis and cancer cell growth. In CRC chemoprevention trials, in general, the incidence of polyps or of the cancer itself is set as the study endpoint. Although the incidence rate of CRC would be the most reliable endpoint, use of this endpoint would be unsuitable for chemoprevention trials, because of the relatively low occurrence rate of CRC in the general population and the long-term observation period that it would necessitate. Moreover, there is an ethical problem in conducting long-term trials to determine whether a test drug might be effective or harmful. Aberrant crypt foci (ACF), defined as lesions containing crypts that are larger in diameter and stain more darkly with methylene blue than normal crypts, are considered as a reliable surrogate biomarker of CRC. Thus, we devised a prospective randomized controlled trial as a preliminary study prior to a CRC chemoprevention trial to evaluate the chemopreventive effect of EPA against colorectal ACF formation and the safety of this drug, in patients scheduled for polypectomy.

METHODS

This study is a multicenter, double-blind, placebo-controlled, randomized controlled trial to be conducted in patients with both colorectal ACF and colorectal polyps scheduled for polypectomy. Eligible patients shall be recruited for the study and the number of ACF in the rectum counted at the baseline colonoscopy. Then, the participants shall be allocated randomly to either one of two groups, the EPA group and the placebo group. Patients in the EPA group shall receive oral 900-mg EPA capsules thrice daily (total daily dose, 2.7 g per day), and those in the placebo group shall receive oral placebo capsules thrice daily. After one month's treatment with EPA/placebo, colonoscopic examination and polypectomy will be performed to evaluate the formation of ACF, and the cell-proliferative activity and cell-apoptotic activity in normal colorectal mucosa and colorectal polyps.

DISCUSSION

This is the first study proposed to explore the effect of EPA against colorectal ACF formation in humans.This trial has been registered in the University hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000008172.

Human colon tissue in organ culture: calcium and multi-mineral-induced mucosal differentiation

We have recently shown that a multi-mineral extract from the marine red algae, Lithothamnion calcareum, suppresses colon polyp formation and inflammation in mice. In the present study, we used intact human colon tissue in organ culture to compare responses initiated by Ca(2+) supplementation versus the multi-mineral extract. Normal human colon tissue was treated for 2 d in culture with various concentrations of calcium or the mineral-rich extract. The tissue was then prepared for histology/immunohistochemistry, and the culture supernatants were assayed for levels of type I procollagen and type I collagen. At higher Ca(2+) concentrations or with the mineral-rich extract, proliferation of epithelial cells at the base and walls of the mucosal crypts was suppressed, as visualized by reduced Ki67 staining. E-cadherin, a marker of differentiation, was more strongly expressed at the upper third of the crypt and at the luminal surface. Treatment with Ca(2+) or with the multi-mineral extract influenced collagen turnover, with decreased procollagen and increased type I collagen. These data suggest that calcium or mineral-rich extract has the capacity to (1) promote differentiation in human colon tissue in organ culture and (2) modulate stromal function as assessed by increased levels of type I collagen. Taken together, these data suggest that human colon tissue in organ culture (supporting in vivo finding in mice) will provide a valuable model for the preclinical assessment of agents that regulate growth and differentiation in the colonic mucosa.

[Efficacy of meloxicam in juvenile polyposis syndrome. A case report]

The Authors present a case of a 11 year-old patient with a history of Juvenile Polyposis Syndrome (JPS), a condition characterized by the occurrence of multiple hamartomatous polyps in the gastrointestinal tract. Patients with JPS are traditionally treated by repeated endoscopic polypectomies and elective surgery. Recent studies reported up-regulation of cyclo-ossigenase 2 (COX-2) in colorectal polyps. Specific COX-2 inhibitors have been withdrown from the market for tromboembolic side effects. However efficacy and safety of preferential selective COX-2 inhibitor has been reported as antiinflammatory drugs also in children. In this patient meloxicam treatment, a preferential selective COX-2 inhibitor, leaded to a significant reduction in the number of colorectal polyps during 3 years follow up.

Overexpression of 5-lipoxygenase in colon polyps and cancer and the effect of 5-LOX inhibitors in vitro and in a murine model

PURPOSE

Arachidonic acid metabolism via the cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) pathways modulates cell growth and apoptosis. Many studies have examined the effects of COX inhibitors on human colorectal cancer, but the role of 5-LOX in colonic cancer development has not been well studied. The purpose of this study was to evaluate the expression of 5-LOX in colonic polyps and cancer and the effect of 5-LOX inhibition on colon cancer cell proliferation.

EXPERIMENTAL DESIGN

Colonic polyps, cancer, and normal mucosa were evaluated for 5-LOX expression by immunohistochemistry. Reverse transcription-PCR was used to establish 5-LOX expression in colon cancer cells. Thymidine incorporation and cell counts were used to determine the effect of the nonspecific LOX inhibitor Nordihydroguaiaretic Acid and the 5-LOX inhibitor Rev5901 on DNA synthesis. A heterotopic xenograft model in athymic mice using HT29 and LoVo human colon cancer cells was used to evaluate the effect of the 5-LOX inhibitor zileuton on tumor growth.

RESULTS

5-LOX is overexpressed in adenomatous polyps and cancer compared with that of normal colonic mucosa. LOX inhibition and 5-LOX inhibition decreased DNA synthesis in a concentration- and time-dependent manner in the Lovo cell line (P < 0.05). Inhibition of 5-LOX in an in vivo colon cancer xenograft model inhibited tumor growth compared with that of controls (P < 0.05).

CONCLUSIONS

This study showed that 5-LOX is up-regulated in adenomatous colon polyps and cancer compared with normal colonic mucosa. The blockade of 5-LOX inhibits colon cancer cell proliferation both in vitro and in vivo and may prove a beneficial chemopreventive therapy in colon cancer.

[Effect of jinfu kang to experimental precancerous colon lesions and urinary metabolites in rat]

OBJECTIVE

: To profile urinary metabolite variations from 1, 2-dimethylhydrazine (DMH)-induced precancerous colon rats, Jinfu Kang treated rats and healthy controls.

METHOD

We used ethyl chloroformate derivatization and gas chromatography-mass spectrometry (GC-MS) based metabonomic method to analyze rat urines.

RESULT

The time-dependent variations of metabolite profile showed a progressive deviation of the metabolism in the model group from the initial pattern over time and a systemic recovery of the metabolism in the treatment group, which is consistent with the histological results. The in-depth analysis indicated that the disorder of tricarboxylic acid cycle (TCA), tryptophan metabolism, polyamine metabolism and gut flora structure were associated with DMH intervention.

CONCLUSION

Metabolic study revealed that Jinfu Kang can effectively reverse metabolic departures in DMH-induced precancerous colon rat, which is consistent with pathological results.

Long-term use of proton pump inhibitors does not affect the frequency, growth, or histologic characteristics of colon adenomas

BACKGROUND

The clinical significance of the trophic effects of long-term proton pump inhibitors (PPI)-related hypergastrinemia on colon polyps remains unknown.

AIM

To study the frequency, growth, and histology of colon polyps in patients on chronic PPI therapy (cases), compared to those not receiving acid suppression (controls).

METHODS

Medical records of 2868 consecutive patients who underwent two or more colonoscopies, performed 3 or more months apart were reviewed. Cases (116) that used PPIs between the two colonoscopies were then compared to controls (194).

RESULTS

Demographics and risk factors for colon cancer were comparable between the two groups. At baseline the mean frequency and size of adenomatous polyps were similar in cases and controls (P > 0.05) and at follow-up, these were 0.89 and 1.18 (P > 0.05; 95% CI of -0.08 to 0.66) and 4.09 mm and 4.00 mm (P > 0.05; 95% CI -2.29 to 2.11), respectively with no significant change. However, control group had a higher mean frequency and size of hyperplastic polyps at baseline as well as at follow-up colonoscopy (P < 0.05).

CONCLUSIONS

The long-term use of PPI does not influence the frequency, growth, or histology of adenomatous polyps, but is associated with a reduction in both baseline and interval development of hyperplastic polyps.

Dietary synbiotics reduce cancer risk factors in polypectomized and colon cancer patients

BACKGROUND

Animal studies suggest that prebiotics and probiotics exert protective effects against tumor development in the colon, but human data supporting this suggestion are weak.

OBJECTIVE

The objective was to verify whether the prebiotic concept (selective interaction with colonic flora of nondigested carbohydrates) as induced by a synbiotic preparation-oligofructose-enriched inulin (SYN1) + Lactobacillus rhamnosus GG (LGG) and Bifidobacterium lactis Bb12 (BB12)-is able to reduce the risk of colon cancer in humans.

DESIGN

The 12-wk randomized, double-blind, placebo-controlled trial of a synbiotic food composed of the prebiotic SYN1 and probiotics LGG and BB12 was conducted in 37 colon cancer patients and 43 polypectomized patients. Fecal and blood samples were obtained before, during, and after the intervention, and colorectal biopsy samples were obtained before and after the intervention. The effect of synbiotic consumption on a battery of intermediate bio-markers for colon cancer was examined.

RESULTS

Synbiotic intervention resulted in significant changes in fecal flora: Bifidobacterium and Lactobacillus increased and Clostridium perfringens decreased. The intervention significantly reduced colorectal proliferation and the capacity of fecal water to induce necrosis in colonic cells and improve epithelial barrier function in polypectomized patients. Genotoxicity assays of colonic biopsy samples indicated a decreased exposure to genotoxins in polypectomized patients at the end of the intervention period. Synbiotic consumption prevented an increased secretion of interleukin 2 by peripheral blood mononuclear cells in the polypectomized patients and increased the production of interferon gamma in the cancer patients.

CONCLUSIONS

Several colorectal cancer biomarkers can be altered favorably by synbiotic intervention.

Chemoprevention of colorectal cancer: two steps forward, one step back?

Colorectal cancer (CRC) is a leading cause of cancer-related morbidity and mortality in the Western world. The poor survival rate has prompted the emphasis on prevention of this disease. Removal of adenomas at colonoscopy is highly effective and is the cornerstone of screening/surveillance strategies. However, screening efforts have had limited impact owing to low compliance with guidelines. Chemoprevention aims to prevent the development or recurrence of precancerous lesions and cancers with the use of compounds that block the carcinogenic process. A major advantage was the establishment and understanding of the multistage process of CRC carcinogenesis. Progress has been remarkable because of the availability of reliable animal models and clinical studies using colonic adenomas as a reliable and economic target for testing chemopreventive agents. Nonsteroidal anti-inflammatory drugs have drawn the most attention. Sulindac and celecoxib were shown to be effective in promoting polyp regression in high-risk individuals with familial adenomatous polyposis. In the more common sporadic setting, the Adenomatous Polyp PRevention On Vioxx® (rofecoxib), Adenoma Prevention with Celecoxib and Prevention of Sporadic Adenomatous Polyps (celecoxib) trials have demonstrated a significant reduction in adenoma recurrence, but important concerns were raised regarding cardiovascular toxicity associated with selective cyclo-oxygenase-2 inhibitors. These landmark studies are very important, as they are a proof-of-concept that we can prevent CRC. More clinical studies are required to better select high-risk patients with safer regimens. Potential advantage versus risk for a given chemopreventive agent will have to be assessed on an individual basis. Currently, the only approved agent for chemoprevention is celecoxib in high-risk individuals with familial adenomatous polyposis.

Hyperplastic polyposis and cancer of the colon with gastrinoma of the duodenum

BACKGROUND

A 64-year-old woman presented to the emergency room with a 3-month history of intermittent abdominal cramps, accompanied by nausea, vomiting, anorexia, and decreased bowel movements consistent with a partial intestinal obstruction. She had a 12-year history of peptic ulcers, which had been treated with histamine-2 blockers.

INVESTIGATIONS

Physical examination, abdominal X-ray, abdominal CT scan, colonoscopy and assessment of gastrin levels.

DIAGNOSIS

Duodenal neuroendocrine neoplasm showing gastrin expression and stage III (T3N2M0), poorly differentiated adenocarcinoma of the cecum arising from hyperplastic polyposis.

MANAGEMENT

Right-sided hemicolectomy with ileocolonic anastomosis, duodenal resection, leucovorin and 5-fluorouracil chemotherapy, annual colonoscopic surveillance, and polypectomy.

Does a selective cyclooxygenase-2 inhibitor (tiracoxib) induce clinically sufficient suppression of adenomas in patients with familial adenomatous polyposis? A randomized double-blind placebo-controlled clinical trial

BACKGROUND

There have been few placebo-controlled randomized double-blind studies of the clinical effects of selective cyclooxygenase-2 (COX-2) inhibitors on the regression of colorectal tumors. This study was designed to examine the regressive effect of a selective COX-2 inhibitor, tiracoxib (JTE-522), on colorectal polyps in patients with familial adenomatous polyposis (FAP), and its safety.

METHODS

Sixty-one patients with FAP diagnosed by Japanese criteria were assigned randomly to receive placebo or JTE-522, at either 150 mg or 200 mg, once daily orally for 26 weeks. Prior to and at the end of the medication period, endoscopy was performed. Adenomas located near an india-ink tattoo injected at the first colonoscopy were identified and measured. The response variables were the percent changes from the baseline in polyp numbers and in specified polyp diameters. Any adverse events that appeared in at least four persons were taken into consideration and compared between the JTE-522 treatment groups and the placebo group.

RESULTS

No change in polyp number (median, 0) was observed in any of the three groups. There were no differences between the placebo group and the two treatment groups in the change in polyp size. JTE-522 was well tolerated.

CONCLUSION

Our findings, in keeping with other reports on COX-2 inhibitors, indicated that the inhibition of a COX-2 with a moderate dose of a selective COX-2 inhibitor did not induce clinically sufficient regression of adenomas in patients with FAP in a limited (6-month) medication period.

Immunomodulation with low dose levamisole in patients with colonic polyps

BACKGROUND

Levamisole (LMS) has immunomodulatory activity, stimulates the immune system of healthy, normal volunteers and has been proposed previously as a colon cancer preventive agent.

METHODS

Patients with a history of colonic polyps who are at increased risk of colon cancer received LMS in a placebo-controlled, double-blinded clinical trail with crossover design. Primary endpoints were immunologic and included flow cytometry of peripheral blood mononuclear cells (PBMCs), measurement of interferon-gamma copy number (IGCN) in PBMCs, and an ex vivo serum immune assay.

RESULTS

No differences were seen in the expression of multiple antigens by flow cytometry pre- and post-LMS. The IGCN partitioned subjects into two distinct groups defined by a gamma-distribution which had a differential response to LMS. Those with low basal IGCN had a lower percentage of CD25 expressing PBMCs and responded to low dose LMS by producing more PBMC-derived interferon-gamma and increasing the expression of CD25 and two NK cell markers, CD16 and CD56. In contrast, subjects with a high basal IGCN responded to low dose LMS with a reduction in PBMC-derived interferon-gamma and a decrease in the expression of CD25.

CONCLUSIONS

In aggregate, these responses suggest that LMS may act as an immunostimulatory agent for one group, those with low basal IGCN, and as an immunosuppressive agent for the other. LMS may not be an optimal agent for most patients with colonic polyps and should be avoided in patients with normal immune function. IGCN may be useful as an immunologic surrogate endpoint biomarker in future cancer prevention trials with immunomodulatory agents.

Butyrate may enhance toxicological defence in primary, adenoma and tumor human colon cells by favourably modulating expression of glutathione S-transferases genes, an approach in nutrigenomics

Butyrate, formed by bacterial fermentation of plant foods, has been suggested to reduce colon cancer risks by suppressing the proliferation of tumor cells. In addition, butyrate has been shown to induce glutathione S-transferases (GSTs) in tumor cell lines, which may contribute to the detoxification of dietary carcinogens. We hypothesize that butyrate also affects biotransformation in non-transformed colon cells. Thus, we have investigated the gene expression of drug metabolism genes in primary human colon tissue, premalignant LT97 adenoma and HT29 tumor cells cultured in an appropriate medium+/-butyrate. A total of 96 drug metabolism genes (including 12 GSTs) spotted on cDNA macroarrays (Superarray; n = 3) were hybridized with biotin-labeled cDNA probes. To validate the expression detected with Superarray, samples of LT97 cells were also analyzed with high density microarrays (Affymetrix U133A), which include biotransformation genes that overlap with the set of genes represented on the Superarray. Relative expression levels were compared across colon samples and for each colon sample+/-butyrate. Compared with fresh tissue, 13 genes were downregulated in primary cells cultivated ex vivo, whereas 8 genes were upregulated. Several genes were less expressed in LT97 (40 genes) or in HT29 (41 and 17 genes, grown for 72 and 48 h, respectively) compared with primary colon tissue. Butyrate induced GSTP1, GSTM2, and GSTA4 in HT29 as previously confirmed by other methods (northern blot/qPCR). We detected an upregulation of GSTs (GSTA2, GSTT2) that are known to be involved in the defence against oxidative stress in primary cells upon incubation with butyrate. The changes in expression detected in LT97 by Superarray and Affymetrix were similar, confirming the validity of the results. We conclude that low GST expression levels were favourably altered by butyrate. An induction of the toxicological defence system possibly contributes to reported chemopreventive properties of butyrate, a product of dietary fibre fermentation in the gut.

Cyclooxygenase-2 inhibition in colorectal cancer: Boom or bust?

Currently, combination chemotherapy represents the standard of care treatment for patients with metastatic colorectal cancer in the United States. Despite recent improvements with the addition of biologic agents, novel treatment approaches are needed to further benefit patients. Cyclooxygenase (COX)-2 inhibition represents one such possibility. COX-2 is highly expressed in colorectal tumor neovasculature and nodal and liver metastases, and expression of COX-2 correlates with tumor stage and patient survival in selected series. COX-2 may be related to colorectal cancer development and propagation through multiple mechanisms, including stimulation of growth, migration, and invasiveness, resistance to apoptosis, and enhancement of angiogenesis. Epidemiologic data suggest nonsteroidal anti-inflammatory drugs (NSAIDs) might prevent development of colorectal cancers, and preclinical data suggest selective COX-2 inhibitors might be additive or synergistic with specific chemotherapeutic agents used in the treatment of colorectal cancer. Despite the lack of published phase I data and the limited, preliminary results of phase II studies, combinations of celecoxib and standard colorectal cancer chemotherapy have entered randomized trials. It is too early to definitively state whether COX-2 inhibition represents a major breakthrough in the treatment of colorectal cancer. Pending the results of ongoing and planned phase III studies, use of COX-2 inhibitors as single agents or incorporation of COX-2 inhibition into combined modality therapy of colorectal cancer should be limited to the setting of clinical trials.

Are we overtreating some patients with rectal cancer?

The definition of overtreatment of rectal cancer is controversial, and thus it is difficult to accurately quantitate its prevalence. All components of rectal cancer treatment are associated with significant potential for morbidity and dysfunction that may have a negative impact on the patient's quality of life. No one would disagree with the tenet that overtreatment should be avoided whenever possible. Despite that consensus, little attention is given in the literature to the issues of overtreatment of rectal cancer. This review article presents a variety of clinical scenarios and summarizes available data demonstrating that overtreatment of some patients with rectal cancer is occurring on a regular basis. It is hoped that this will stimulate clinicians to critically review their own practices to eliminate such overtreatment. Development of new clinical trials to determine whether current practice guidelines are promoting overtreatment of selected rectal cancer patients is proposed.

Dose-dependent suppression of hyperlipidemia and intestinal polyp formation in Min mice by pioglitazone, a PPAR gamma ligand

In our previous study, a peroxisome proliferator-activated receptor gamma (PPAR gamma) agonist, pioglitazone, suppressed both hyperlipidemia and intestinal polyp formation in Apc(1309) mice at doses of 100 and 200 ppm in the diet. In contrast, it has been reported that doses of 1500 or 2000 ppm of another PPAR gamma agonist, troglitazone, enhanced colon polyp development in Min mice. In the present study, we therefore investigated the effects of a wide range of pioglitazone doses on both hyperlipidemia and intestinal polyp formation in Min mice. Serum triglycerides and very low density lipoprotein (VLDL) cholesterol in the basal diet group were elevated to levels 13-15 times higher than those in the wild-type counterparts at 20 weeks of age. They were reduced dose-dependently by treatment with 100, 200, 400 and 1600 ppm pioglitazone from 6-20 weeks of age with suppression to almost the wild-type level at the highest dose. Moreover, up-regulation of the liver mRNA levels for lipoprotein lipase (LPL) was evident in the pioglitazone-treated animals. Dose-dependent reduction of intestinal polyps was observed in Min mice given 100-1600 ppm for 14 weeks, total numbers being decreased to 63-9% of the control value. A suppressive effect of pioglitazone on colon polyp formation was also found. The PPAR gamma agonist, pioglitazone, may thus be a promising candidate chemopreventive agent for colon cancer.

Effect of calcium supplementation on the risk of large bowel polyps

BACKGROUND

Clinical trials have shown that calcium supplementation modestly decreases the risk of colorectal adenomas. However, few studies have examined the effect of calcium on the risk of different types of colorectal lesions or dietary determinants of this effect.

METHODS

Our analysis used patients from the Calcium Polyp Prevention Study, a randomized, double-blind, placebo-controlled chemoprevention trial among patients with a recent colorectal adenoma. Nine hundred thirty patients were randomly assigned to calcium carbonate (1200 mg/day) or placebo. Follow-up colonoscopies were conducted approximately 1 and 4 years after the qualifying examination. We used general estimating equation (GEE) and generalized linear regression analyses to compute risk ratios and 95% confidence intervals (CIs) to assess the effect of calcium treatment versus placebo on the risk of hyperplastic polyps, tubular adenomas, and more advanced lesions. Additionally, we used GEE analyses to compare the calcium treatment effects for various types of polyps with that for tubular adenomas. We also examined the interaction between calcium treatment and baseline intake of dietary calcium, fat, and fiber. All P values were obtained using Wald tests based on the corresponding models. All tests of statistical significance were two-sided.

RESULTS

The calcium risk ratio for hyperplastic polyps was 0.82 (95% CI = 0.67 to 1.00), that for tubular adenomas was 0.89 (95% CI = 0.77 to 1.03), and that for histologically advanced neoplasms was 0.65 (95% CI = 0.46 to 0.93) compared with patients assigned to placebo. There were no statistically significant differences between the risk ratio for tubular adenomas and that for other types of polyps. The effect of calcium supplementation on adenoma risk was most pronounced among individuals with high dietary intakes of calcium and fiber and with low intake of fat, but the interactions were not statistically significant.

CONCLUSION

Our results suggest that calcium supplementation may have a more pronounced antineoplastic effect on advanced colorectal lesions than on other types of polyps.

[Non-steroidal anti-inflammatory agents for chemoprevention of colorectal polyps: a meta-analysis]

OBJECTIVE

To assess whether or not non-steroidal anti-inflammatory agents (NSAIDs) might prevent colorectal polyps.

METHODS

A systematic review of all relevant randomized controlled trials was performed. We searched all randomized controlled trials of chemoprevention of colorectal polyps. Abstracts was included.

RESULTS

8 trials were assessed in the final systematic analysis. We found a sufficient evidence to support that aspirin might prevent the development of colorectal adenomas in comparing with placebo group in two trails of high quality and large sample (P = 0.003). However, there is no evidence to support that sulindac and celecoxib might cure or prevent colorectal adenomas or familial adenomatous polyposis (P > 0.05) and also no evidence to support that dosage of NSAIDs is related with the result of prevention of colorectal adenomas. It was shown that regular aspirin use for 30-60 months cannot reduce the risk of colorectal cancer (P = 0.8). No significant difference in the number of adverse events was found between patients taking NSAIDs and those given placebo (P = 0.9).

CONCLUSIONS

Aspirin might prevent the development of colorectal adenomas, but there is no evidence to support that sulindac and celecoxib might cure or prevent colorectal adenomas or familial adenomatous polyposis and that regular aspirin use might reduce the risk of colorectal cancer.

A randomized, double-blind, placebo-controlled trial of the effects of rofecoxib, a selective cyclooxygenase-2 inhibitor, on rectal polyps in familial adenomatous polyposis patients

PURPOSE

The aim of this study was to examine the effect of a specific cyclooxygenase-2 inhibitor, rofecoxib, on rectal polyps in familial adenomatous polyposis patients.

EXPERIMENTAL DESIGN

This was a randomized, double-blind, placebo-controlled study of the efficacy and safety of rofecoxib in the rectum. Initially, 21 patients were assigned randomly in a 1:1 ratio to receive either 25 mg rofecoxib once a day or a placebo p.o. for 9 months. Patients underwent endoscopy at the beginning of the study and then every 3 months thereafter. We reviewed the videotapes to measure the number and size of polyps in the same area throughout the study period in each individual patient.

RESULTS

The polyp number, measured as the percentage of change from the baseline values, was significantly decreased in the rofecoxib group at 3, 6, and 9 months. At 9 months, the polyp number in the rofecoxib group decreased by 6.8% from the baseline values, whereas that in the placebo group increased by 3.1%. The 9.9% difference between the rofecoxib and placebo groups was statistically significant (P = 0.004). At 9 months, the rofecoxib group showed a significant reduction from the baseline in polyp size as compared with the placebo group (-16.2% versus 1.5%; P < 0.001). There was no statistically significant increase in the incidence of any adverse events in treatment with rofecoxib compared with placebo (P = 0.922).

CONCLUSIONS

In this study, once-daily treatment with 25 mg rofecoxib, a cyclooxygenase 2-specific inhibitor, significantly decreased the number and size of rectal polyps in familial adenomatous polyposis patients.

Use of activated recombinant human factor VII (rhFVIIa) for colonic polypectomies in patients with cirrhosis and coagulopathy

The prevalence of colonic polyps in patients with cirrhosis appears to be higher than that of the general population. The current practice for a polypectomy in a coagulopathic cirrhotic patient involves the reversal of the coagulopathy using fresh frozen plasma (FFP) prior to the polypectomy, usually at a second colonoscopy. The use of FFP is associated with many problems, particularly that of volume overload. Here we report four cases with advanced cirrhosis and severe coagulopathy that underwent polypectomies by snare cautery after an intravenous bolus infusion of recombinant human factor VIIa (rhFVIIa). The dose used was 120 microg/kg, which provided normalization of the coagulation parameters for 10-16 hr. The immediate use of rhFVIIa reduced the utilization of resources and enabled the performance of the polypectomies at the initial colonoscopy. No postpolypectomy bleeding was noted. The high cost of the drug is the only obstacle to a wider use of rhFVIIa for this purpose. The cost of the drug, however, is offset substantially by the cost of hospitalization for the administration of FFP, the cost of a second colonoscopy, and the charges associated with a second utilization of the endoscopy suite.

Plasma basic fibroblast growth factor levels in colorectal cancer: a clinically useful assay?

Angiogenic cytokines in the plasma and serum of cancer patients may serve as 'surrogate' markers of tumour neoangiogenesis. Serum VEGF correlates with disease stage in colorectal cancer (CRC), but the role of bFGF in CRC is uncertain. This study aimed to assess plasma bFGF levels in CRC patients before treatment, during chemoradiotherapy and at one-year follow-up. Plasma samples were taken from 124 CRC patients, 26 polyp patients and 55 controls, and bFGF levels were measured by ELISA. 19 patients underwent pre-operative chemoradiotherapy. One-year follow-up samples were available from 48 disease-free patients and 18 patients with progressive disease. There were no detectable differences between plasma bFGF levels in polyp, Dukes' A or B patients (4.55, 5.77, 4.25 pg/ml, respectively), but there was a significant increase in metastatic CRC patients [Dukes' C and D (7.42 and 6.6 pg/ml; P = 0.004 and 0.048, respectively)], relative to median control levels of 4.14 pg/ml. At follow-up, there was a significant fall in plasma bFGF levels in disease-free patients (pre-op 6.09 and follow-up 3.45 pg/ml, P = 0.0004), but a non-significant rise in 18 patients with progressive disease (pre-treatment 5.90 and follow-up 9.99 pg/ml, P = 0.33). Pre-treatment plasma bFGF in patients receiving chemo-radiotherapy was similar in those with responsive and non-responsive tumours. There were no detectable changes in plasma bFGF through the adenoma-carcinoma sequence or patient groups with non-metastatic cancers. Elevated plasma bFGF was, however, associated with metastatic spread. The significant fall in bFGF in disease-free patients following therapy suggests that bFGF may be useful in clinical practice.

Cap polyposis cured by Helicobacter pylori eradication therapy

The pathogenesis of cap polyposis remains unknown. Here, we report a patient with cap polyposis that developed simultaneously in the colon and stomach, and which regressed after Helicobacter pylori eradication. A 63-year-old man was diagnosed as having cap polyposis with mucoid stool, diarrhea, and bleeding on defecation. Following 5 weeks of total parenteral nutrition, his symptoms and hypoproteinemia improved and he was discharged, although follow-up colonoscopic findings revealed no improvement. Subsequent gastroscopy revealed diffusely erosive polyps with cap-like "fur" from the angle to the antrum of the stomach, similar to the lesions observed in the colon. Because H. pylori infection was demonstrated in the stomach, eradication therapy was administered. After this treatment, his symptoms immediately disappeared, and the polypoid lesions in the colon and stomach had completely disappeared 8 months later. Because there have been no previous reports of a relationship between H. pylori and cap polyposis, this case is of great interest.

PC-SPES inhibits colon cancer growth in vitro and in vivo

PC-SPES is a mixture of eight herbs with antiproliferative activity in prostate cancer cell lines and antitumor effects in animal models of prostate cancer. In addition, evidence of clinical efficacy in advanced prostate cancer has been reported. PC-SPES has also been shown to have antitumor activity against several other cancer cell lines including breast and neuroepithelial cancer, melanoma, and leukemia cell lines. Because of these findings, we investigated the effects of PC-SPES in vitro in colon cancer cell lines SW480, SW620, and DLD-1 and in vivo in the Apc(min) mouse, a murine model for intestinal carcinogenesis. For the in vitro studies, colon cancer cell lines were exposed to an ethanolic extract of PC-SPES compared with a diluent control [ethanol < or = 0.3% (v/v)]. PC-SPES resulted in a marked suppression of cell proliferation in all colon cancer cells studied. PC-SPES (3 micro l/ml) caused a 95% inhibition of cell proliferation of the DLD-1 colon cancer cell line, and similar results were observed in the SW480 and SW620 colon cancer cell lines. Cell cycle analysis demonstrated a drastic (> or =60%) accumulation of cells in the G(2)-M phase with a concomitant decrease of cells in the G(0)-G(1) phase in all colon cancer cell lines studied after treatment with PC-SPES (1.5 micro l/ml for 48 h). Western blot analysis demonstrated a decrease in protein levels of beta-tubulin in the SW620 cell line exposed to PC-SPES. Terminal deoxynucleotidyl transferase-mediated nick end labeling analysis revealed an increase in apoptotic colon cancer cells incubated with PC-SPES. For the in vivo studies, female 4-5-week-old Apc(min) mice were randomized to two groups: a PC-SPES-treated group (n = 11) received 250 mg/kg/day (0.2 ml) PC-SPES via gastrointestinal gavage; and a control group (n = 10) received 0.2 ml of the vehicle solution (1.5% carboxymethylcellulose with 0.2% Tween 20) via gastrointestinal gavage. Both groups were treated five times a week for 10 weeks. After treatment, the gastrointestinal tract was dissected for polyp scoring by two observers blinded to treatment. The Apc(min) mice given PC-SPES had a 58% reduction in tumor number and a 56% decrease in tumor load. No effect on either food intake or body weight was observed in the treated versus sham groups. The present study is the first to report the potent activity of PC-SPES against colon cancer. Both cell cycle arrest and apoptosis occurred after treatment with PC-SPES. This suggests that the components of this herbal mixture, either independently or in combination, acted in colon cancer, resulting in a drastic effect on tumor initiation and tumor progression.

Effect of folate supplementation on mucosal cell proliferation in high risk patients for colon cancer

AIMS

Intracellular folate deficiency has been implicated in colonic carcinogenesis in epidemiological studies and animal and human cancer models. Our aim was to determine the effect of folate supplementation on patients with recurrent adenomatous polyps using rectal mucosal cell proliferation as a biomarker.

PATIENTS AND METHODS

Eleven patients with recurrent adenomatous polyps of the colon were randomised into a treatment group (n=6) receiving a dietary supplement of 2 mg folic acid per day for three months and a control group (n=5) receiving a placebo. Rectal biopsies where taken at 10 cm from the anal verge prior to supplementation and repeated at four, 12, and 18 weeks from the start of the supplementation. Each biopsy was immediately incubated in culture medium enriched with bromodeoxyuridine (BrdU). The S phase cells which incorporated BrdU into their DNA were identified following immunohistochemical staining. Twenty five orientated crypts were identified for each time point and the number and position of BrdU positive and BrdU negative cells were counted. BrdU labelling indices (LIs) were calculated for the entire crypt and for each of five equal compartments running consequently from the base to the luminal surface.

RESULTS

The LI of the treatment group (9.1 (6.7, 12.3)) and the control group (9.3 (7.8, 10.3)) were comparable at the start. Over the duration of the supplementation period, LI in the control group did not alter significantly (9.3 (7.8, 10.3) v 9.6 (8.9, 10.4)). However, LI of the folate treated group was lowered after 12 weeks of supplementation (9.1 (6.7, 12.3) v 7.4 (5.3, 9.6)). Analysis of the LI for compartments within the crypt showed that the most significant drop in number of proliferating cells was in the upper most regions of the crypt.

CONCLUSION

These data indicate that (a) folate supplementation decreases colonic mucosal cell proliferation in a high risk group for colon cancer and (b) the most significant reduction takes place at the luminal aspect of the crypt.

Model of estimated rates of colorectal cancer from polyp growth by year of surveillance

OBJECTIVE

Most studies show protective effects of non-steroidal anti-inflammatory drugs (NSAIDs) against polyps and colorectal cancers (CRCs) of up to 50%. Current models are unable to directly estimate changes in effects of chemoprevention on CRCs. The purpose is to develop a model to examine effects of changes in growth rates of polyps on surveillance intervals and risk of CRC.

METHODS

The growth model simulates 500 people after polypectomy, estimating number and size of polyps annually over 10 years. Each polyp is assigned a random growth rate consistent with distributions of empirically observed growth assumed to follow a log linear model. Rates of CRC were calculated from largest polyps distributed to people.

RESULTS

Simulated distributions of polyps and CRCs closely match empirical estimates which confirms the usefulness of the model. If polyp growth is 25% of normal, the number of cancers by year 10 after index colonoscopy decrease from 146 to only 57/100 000 for those in risk group 0 (no polyps at index colonoscopy) and from 840 to 124/100 000 for those of risk group 3 (4 or more polyps).

CONCLUSIONS

This is the first model based on polyp growth rates. The CRC rates suggest that for those with no polyps on index colonoscopy, surveillance may be as for people of average risk (7-10 years), whereas those with one polyp or more need more surveillance (2-5 years). The use of the model is the indication that surveillance intervals could be increased by as much as 2-10 years if the growth rates of polyps are slowed.

Effects of difluoromethylornithine chemoprevention on audiometry thresholds and otoacoustic emissions

OBJECTIVES

To determine the effects of long-term, low-dose difluoromethylornithine (DFMO) on audiometric thresholds and distortion product otoacoustic emission (DPOAE) levels in humans.

DESIGN

A prospective, randomized, placebo-controlled phase 2 clinical trial of DFMO in participants with a prior adenomatous colonic polyp.

SETTING

Academic tertiary care referral center.

PARTICIPANTS

One hundred twenty-three volunteer subjects with colorectal polyps and normal hearing for the frequencies 250 through 2000 Hz.

INTERVENTIONS

Subjects were randomized to receive placebo or oral DFMO at daily dosages between 0.075 and 0.4 g/m(2) of body surface area for 12 months.

OUTCOME MEASURES

Pure-tone audiometric thresholds for the frequencies 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz and DPOAE levels were measured at baseline and 1, 3, 6, 9, and 12 months after starting treatment with DFMO or placebo and 3 months after cessation of treatment if there was a suggestion of possible changes at the 12-month measurement.

RESULTS

At these low dosages, there was little evidence for shifts in auditory pure-tone thresholds, and there were no statistically significant shifts in DPOAE levels. For auditory pure-tone thresholds, there was a subtle, approximately 2- to 3-dB hearing level decrease in hearing sensitivity for the 2 higher DFMO dosages, but only at the 2 lowest frequencies, 250 and 500 Hz.

CONCLUSIONS

Administration of low-dose DFMO for 12 months did not produce hearing loss, in contrast to prior studies that used higher dosages.

Growth and recurrence of colorectal polyps: a double-blind 3-year intervention with calcium and antioxidants

BACKGROUND

Dietary calcium and antioxidants have been suggested as protective agents against colorectal cancer. This has been supported by animal experimental studies, case control and cohort studies.

MATERIALS AND METHODS

In a prospective intervention study of colorectal adenomas, and intermediary stage in colorectal carcinogenesis, 116 polyp-bearing patients received a placebo-controlled daily mixture of beta-carotene 15 mg, vitamin C 150 mg, vitamin E 75 mg, selenium 101 microg, and calcium (1.6 g daily) as carbonate for a period of 3 years with annual colonoscopic follow-up to test if the mixture was able to reduce polyp growth or recurrence. All polyps of < 10 mm at enrollment or follow-up were left unresected until the end of the study.

RESULTS

87-91% of the patients attended the annual endoscopic follow-up investigations, and 19% of the patients dropped out of the medical intervention. The rest consumed 85% of the total amount of tablets over the 3 years. The fecal calcium concentration was 2.3-2.7 times higher in patients taking active medication compared to the placebo group. Diet registration showed that, when adding the intake of antioxidants and calcium from diet and intervention, there was a significant difference between the intake of these substances in the active and the placebo group. No difference was detected in the growth of adenomas between the active and the placebo group from year to year and for the total study period. Moreover, there was no effect on polyps of < 5 or 5-9 mm, or on polyps in the different colonic segments analyzed separately. A reduced growth of adenomas was found in patients <60 years of age taking active medication (n = 8) compared to those taking placebo (n = 6; mean difference 2.3 mm; 95% CI 0.26-4.36). There was a significantly lower number of patients free of new adenomas in the placebo group compared to those taking active medication as tested by logistic regression and Kaplan-Meier analysis (log-rank test p value 0.035). Subgroup analysis showed that only the group of patients with no family history of colorectal cancer, those with only one adenoma at inclusion, and those <65 years benefitted from the intervention medication.

CONCLUSION

The study did not find an overall effect on polyp growth. Our data, however, may support a protective role of calcium and antioxidants on new adenoma formation.

Colorectal hyperplastic polyps and risk of recurrence of adenomas and hyperplastic polyps. Polyps Prevention Study

We examined data from two large colorectal chemoprevention trials for possible associations of hyperplastic polyps and adenomas with subsequent development of these lesions. Hyperplastic polyps do not predict metachronous adenomas.

Rectal cancer after sulindac therapy for a sporadic adenomatous colonic polyp

Like adenomatous polyps in familial adenomatous polyposis, some sporadic colorectal polyps have been reported to regress in response to sulindac administration. However, a rapidly growing invasive rectal cancer developed in one of 15 patients with sulindac-treated sporadic adenomatous colorectal polyps 16 months after sulindac treatment. In this patient, both the adenomatous polyp that responded partially to sulindac and the rectal cancer developing after sulindac therapy showed immunostaining for cyclooxygenase-2. Although short term sulindac therapy seems to be able to cause some adenomatous colorectal polyps to regress, 4 months of sulindac therapy may not reliably prevent colorectal cancer development in these patients.

Synthesis and intestinal metabolism of ursodeoxycholic acid conjugate with an antiinflammatory agent, 5-aminosalicylic acid

5-Aminosalicylic acid conjugate of ursodeoxycholic acid was synthesized in above 90% yield by adding a basic solution of 5-aminosalicylic acid into the mixed anhydride formed with ursodeoxycholic acid and ethyl chloroformate. The 5-aminosalicylic acid conjugate of ursodeoxycholic acid was poorly secreted into the bile and was deconjugated with cholylglycine hydrolase and Clostridium perfringens, that deconjugate naturally occurring glycine and taurine conjugates of bile acids. However, ursodeoxycholic acid 5-aminosalicylic acid conjugate was not absorbed from the duodenum but was concentrated in the colon where it was partially hydrolyzed by the intestinal bacteria to ursodeoxycholic acid and 5-aminosalicylic acid. We believe that this unique conjugation of ursodeoxycholic acid with 5-aminosalicylic acid may facilitate the transport of both 5-aminosalicylic acid and ursodeoxycholic acid to the colon and may be useful for the treatment of colonic inflammatory bowel diseases, ulcerative colitis and Crohn's disease.

Enrichment of the more hydrophilic bile acid ursodeoxycholic acid in the fecal water-soluble fraction after feeding to rats with colon polyps

We recently showed that feeding the cytoprotective bile acid ursodeoxycholic acid (UDCA) to rats resulted in significant reduction in polyps and especially cancers, both in number and size (D. L. Earnest et al., Cancer Res., 54: 5071-5074, 1994). Because fecal secondary bile acids [particularly deoxycholic acid (DCA)] are considered to promote formation of colon adenomas and cancer, we have now attempted to find a relationship between polyp reduction and fecal secondary bile acids after feeding UDCA to these rats. We examined the fecal bile acids in rats with polyps and compared them with fecal bile acids in control rats and also determined the bile acid composition in fecal aqueous phase, which is in direct contact with the colon epithelium and may be physiologically more active. Treatment with azoxymethane did not significantly alter fecal bile acid composition in the rats. Cholic acid feeding resulted in greatly increased proportions of DCA (82% of total bile acids versus 18% in control rats). On the other hand, UDCA feeding significantly reduced the proportion of fecal DCA (2% in control rats fed UDCA and 3% in rats also treated with azoxymethane). In control rats, 96% of the bile acids were present in the water-insoluble fraction and 4% in the water-soluble fraction. The major insoluble bile acids included DCA and hyodeoxycholic acid (73% of total bile acids). In contrast, the muricholic acids were concentrated in the soluble fraction (37%). When 0.4% UDCA was added to the diet, lithocholic acid increased in the insoluble fraction (40 versus 1%), but the hydrophilic UDCA and muricholic acids were enriched in the water-soluble fraction (37 and 43%, respectively). Thus, the hydrophobic bile acids were distributed predominantly in the water-insoluble fraction, whereas the hydrophilic bile acids were distributed preferentially in the water-soluble fraction. These data suggest that UDCA may prevent colon tumors and polyps by countering the toxic effect of DCA and enhancing the possible cytoprotective effects of UDCA and muricholic acids in the water-soluble fraction in the feces of rat.

Colonoscopy for frank bloody stools associated with cancer chemotherapy

Diarrhea is a common complication of cancer chemotherapy, while bloody stool is rare. Pseudomembranous colitis has been reported as causing bloody diarrhea after chemotherapy. In this report, we describe nine consecutive patients who presented frank bloody stools within one month after cancer chemotherapy. Patients with a history of pelvic irradiation or with a previously identified colorectal tumor were excluded. Among nine patients, bleeding from tumor undetected before chemotherapy was seen in three, pseudomembranous colitis in four, ischemic colitis in one and methicillin-resistant Staphylococcus aureus enterocolitis in one. Of the three tumors, one was an adenomatous polyp and the other two were metastatic tumors. Two of the four patients with pseudomembranous colitis had not received antibiotics before the onset of colitis. Causes of bloody stools after chemotherapy were various and colonoscopy played an important role in diagnosis and prompt therapy.