Artesunate inhibits intestinal tumorigenesis through inhibiting wnt signaling.

Artesunate (ART) is a clinically approved antimalarial drug and was revealed as a candidate of colorectal cancer chemopreventive agents in our drug screening system. Here, we aimed to understand the suppressive effects of ART on intestinal tumorigenesis. In vitro, ART reduced T-cell factor/lymphoid enhancer factor (TCF/LEF) promoter transcriptional activity. In vivo, ART inhibited intestinal polyp development. We found that ART reduces TCF1/TCF7 nuclear translocation by binding the Ras-related nuclear protein (RAN), suggesting that ART inhibits TCF/LEF transcriptional factor nuclear translocation by binding to RAN, thereby inhibiting Wnt signaling. Our results provide a novel mechanism through which artesunate inhibits intestinal tumorigenesis.

Effects of supplemental calcium and vitamin D on tight-junction proteins and mucin-12 expression in the normal rectal mucosa of colorectal adenoma patients.

The physical gut barrier, comprised of a thick mucus layer and the epithelium, plays an important role in defense against microbes and foreign antigens. Calcium and vitamin D may be involved in maintaining the integrity of the intestinal mucosal barrier, the dysfunction of which may lead to endotoxemia and inflammation, and contribute to colorectal carcinogenesis. We investigated supplemental calcium (1200 mg, daily) and/or vitamin D3 (1000 IU daily) effects on intestinal barrier function-related biomarkers in a subset of 105 participants from a large colorectal adenoma recurrence chemoprevention clinical trial. We assessed expression of the tight junction proteins claudin-1 (CLDN1), occludin (OCLD), and mucin-12 (MUC12) in the normal-appearing colorectal mucosa using standardized, automated immunohistochemistry and quantitative image analysis. Following 1 year of treatment, in the calcium relative to the no calcium group, the CLDN1, OCLD, and MUC12 expression increased by 14% (P = 0.17), 23% (P = 0.11), and 22% (P = 0.07), respectively. In secondary analyses, the estimated calcium treatment effects were greater among participants with baseline serum 25-OH-vitamin D concentrations below the median value of 22.69 ng/mL (CLDN1: 29%, P = 0.04; OCLD: 36%, P = 0.06; MUC12: 35%, P = 0.05). There were no biomarker expression changes in the vitamin D3 alone group; however, modest increases were found in the combined calcium/vitamin D3 group. At baseline, obesity, history of a sessile-serrated adenoma, colorectal MIB-1/Ki-67 expression, and a family history of colorectal cancer were associated with CLDN1, OCLD, and MUC12 expression. Our study supports continued investigation of factors that could affect intestinal mucosal barrier integrity relevant to colorectal carcinogenesis.

[Desmoid tumors in an adolescent girl with familial adenomatous polyposis]. / Tumeurs desmoïdes dans le cadre d'une polypose adénomateuse familiale chez une adolescente.

Desmoid tumors (DT) are rare and nonmetastasizing fibroblastic neoplasms, characterized by local invasiveness. They occur sporadically or arise in the context of familial adenomatous polyposis (FAP; 5-10% of cases). Most cases develop sporadically in young adults, but some cases also occur in children. We report the case of an adolescent girl with FAP and DT, and we discuss the therapeutic strategies. An adolescent girl with FAP underwent surgery at the age of 14 years with total proctocolectomy. She had a neo-mutation in the APC gene at codon 1068, which is not usually associated with DT. Three years later, she had painful defecations. Imaging showed two abdominal DT. After a multidisciplinary team meeting, the patient was refused for surgery, and medical treatment with antihormonal agents and nonsteroidal anti-inflammatory drugs was started. Imaging 18 months later showed DT stabilization, but the patient had difficulties to control chronic pains, which required morphine treatment, hypnotic sessions, and transcutaneous electric nerve stimulation. This case highlights the importance of DT screening in patients with FAP, mainly after surgery, regardless of their age and genetic mutation. Progress remains to be made in determining DT risk factors and in developing treatment. DT are still difficult to cure because of their potential for local invasion and local recurrence, and need to be managed by a multidisciplinary team.

Tumor-selective proteotoxicity of verteporfin inhibits colon cancer progression independently of YAP1.

Yes-associated protein 1 (YAP1) is a transcriptional coactivator in the Hippo signaling pathway. Increased YAP1 activity promotes the growth of tumors, including that of colorectal cancer (CRC). Verteporfin, a drug that enhances phototherapy to treat neovascular macular degeneration, is an inhibitor of YAP1. We found that verteporfin inhibited tumor growth independently of its effects on YAP1 or the related protein TAZ in genetically or chemically induced mouse models of CRC, in patient-derived xenografts, and in enteroid models of CRC. Instead, verteporfin exhibited in vivo selectivity for killing tumor cells in part by impairing the global clearance of high-molecular weight oligomerized proteins, particularly p62 (a sequestrome involved in autophagy) and STAT3 (signal transducer and activator of transcription 3; a transcription factor). Verteporfin inhibited cytokine-induced STAT3 activity and cell proliferation and reduced the viability of cultured CRC cells. Although verteporfin accumulated to a greater extent in normal cells than in tumor cells in vivo, experiments with cultured cells indicated that the normal cells efficiently cleared verteporfin-induced protein oligomers through autophagic and proteasomal pathways. Culturing CRC cells under hypoxic or nutrient-deprived conditions (modeling a typical CRC microenvironment) impaired the clearance of protein oligomers and resulted in cell death, whereas culturing cells under normoxic or glucose-replete conditions protected cell viability and proliferation in the presence of verteporfin. Furthermore, verteporfin suppressed the proliferation of other cancer cell lines even in the absence of YAP1, suggesting that verteporfin may be effective against multiple types of solid cancers.

Berberine potently attenuates intestinal polyps growth in ApcMin mice and familial adenomatous polyposis patients through inhibition of Wnt signalling.

As a traditional anti-inflammatory Chinese herbal medicine, Alkaloid berberine has been recently reported to exhibit anti-tumour effects against a wide spectrum of cancer. However, the mechanism was largely unknown. Gene chip array reveals that with berberine treatment, c-Myc, the target gene of Wnt pathway, was down-regulated 5.3-folds, indicating that berberine might inhibit Wnt signalling. TOPflash analysis revealed that Wnt activity was significantly reduced after berberine treatment, and the mechanism of which might be that berberine disrupted ß-catenin transfer to nucleus through up-regulating the expression of adenomatous polyposis coli (APC) gene and stabilized APC-ß-catenin complex. Berberine administration in ApcMin/+ mice exhibited fewer and smaller polyps in intestine, along with reduction in cyclin D1 and c-Myc expression. In clinical practice, oral administration of berberine also significantly reduced the familial adenomatous polyposis patients' polyp size along with the inhibition of cyclin D1 expression in polyp samples. These observations indicate that berberine inhibits colon tumour formation through inhibition of Wnt/ß-catenin signalling and berberine might be a promising drug for the prevention of colon cancer.

Nuclear orphan receptor NR4A2 confers chemoresistance and predicts unfavorable prognosis of colorectal carcinoma patients who received postoperative chemotherapy.

BACKGROUND: NR4A2, an orphan nuclear receptor essential in neuron generation, has been recently linked to inflammatory and metabolic pathways of colorectal carcinoma (CRC). However, the effects of NR4A2 on chemo-resistance and postoperative prognosis of CRC remain unknown. METHODS: NR4A2 was transfected into CRC cells to investigate its effects on chemo-resistance to 5-fluorouracil and oxaliplatin and chemotherapeutics-induced apoptosis. We also investigated prostaglandin E2 (PGE2)-induced NR4A2 expression and its effect on chemo-resistance. Tissue microarrays including 51 adenoma, 14 familial adenomatous polyposis with CRC, 17 stage IV CRC with adjacent mucosa and 682 stage I-III CRC specimens were examined immunohistochemically for NR4A2 expression. Median follow-up time for stage I-III CRC patients was 53 months. RESULTS: Ectopic expression of NR4A2 increased the chemo-resistance, and attenuated the chemotherapeutics-induced apoptosis. Transient treatment of PGE2 significantly up-regulated NR4A2 expression via protein kinase A pathway and increased the chemo-resistance. NR4A2 expression in epithelials consecutively increased from adenoma, adjacent mucosa to CRC (P(trend)<0.001). In multivariate Cox regression analyses, high NR4A2 expression in cancer nuclei (immunoreactive score ≥ 4) significantly predicted a shorter disease-specific survival (DSS) of CRC patients (hazard ratio [HR]=1.88, P=0.024). High NR4A2 expression specifically predicted a shorter DSS of colon cancer patients (dichotomisation, HR=2.55, log-rank test P=0.011), especially for those who received postoperative 5-fluorouracil/leucovorin plus oxaliplatin (FOLFOX) chemotherapy (3-score range, HR=1.86, log-rank test P=0.020). CONCLUSION: High expression of NR4A2 in CRC cells confers chemo-resistance, attenuates chemotherapeutics-induced apoptosis, and predicts unfavorable prognosis of colon cancer patients, especially for those who received postoperative chemotherapy. NR4A2 may be prognostic and predictive for colon cancer.

Prevention of familial adenomatous polyp development in APC min mice and azoxymethane-induced colon carcinogenesis in F344 Rats by ω-3 fatty acid rich perilla oil.

The present study explored the preventive effects of perilla oil, rich in α-linolenic acid, in rodent models of colon tumorigenesis. Six-week-old male F344 rats were fed diets containing 5% corn oil or 10 or 20% perilla oil. Colonic aberrant crypt foci (ACF) were induced by azoxymethane (AOM) and colonic ACF were evaluated. In familial adenomatous polyposis mode, APC(min) mice fed with 20% corn oil or perilla oil for 80 days and intestines were evaluated for polyps. Multiple colonic mucosal and polyp samples were assayed for the expression and activity of cyclooxygenase COX-isoforms. Dietary perilla oil produced a dose-dependent inhibition of AOM-induced colonic ACF formation (by 35-53%, P < 0.01-0.005) and reduced the number of foci with ≥ 4 crypts/focus (by 38-50%, P < 0.01-0.001) in F344 rats. Dietary perilla oil significantly inhibited development of small intestinal (>69%, P < 0.0001) and colon tumors (>52%, P < 0.03) in APC(min) mice. Administration of perilla oil produced lower levels of type-2 prostaglandins (38-53%) from COX-activities in polyps of APC(min) mice. These observations demonstrate that dietary perilla oil rich in ω-3 fatty acids possesses preventive activity against intestinal neoplastic lesions, both in FAP in genetically-predisposed tissues, as well as against chemically induced preneoplastic lesions in the colon.

Thymoquinone attenuates tumor growth in ApcMin mice by interference with Wnt-signaling.

BACKGROUND: Patients with familial adenomatous polyposis (FAP) are at increased risk for the development of colorectal cancer. Surgery and chemoprevention are the most effective means to prevent cancer development. Thymoquinone (TQ) is considered the main compound of the volatile Nigella sativa seed oil and has been reported to possess anticarcinogenic properties. In this study we evaluated the chemopreventive properties of TQ in a mouse model of FAP. METHODS: APCMin mice were fed with chow containing 37.5 mg/kg or 375 mg/kg TQ for 12 weeks. H&E stained intestine tissue sections were assessed for tumor number, localization, size, and grade. Immunohistochemistry for ß-catenin, c-myc, Ki-67 and TUNEL-staining was performed to investigate TQ's effect on major colorectal cancer pathways. TQ's impact on GSK-3ß and ß-catenin were studied in RKO cells. RESULTS: 375 mg/kg but not 37.5 mg/kg TQ decreased the number of large polyps in the small intestine of APCMin mice. TQ induced apoptosis in the neoplastic tissue but not in the normal mucosa. Furthermore, upon TQ treatment, ß-catenin was retained at the membrane and c-myc decreased in the nucleus, which was associated with a reduced cell proliferation in the villi. In vitro, TQ activated GSK-3ß, which induced membranous localization of ß-catenin and reduced nuclear c-myc expression. CONCLUSIONS: In summary, TQ interferes with polyp progression in ApcMin mice through induction of tumor-cell specific apoptosis and by modulating Wnt signaling through activation of GSK-3ß. Nigella sativa oil (or TQ) might be useful as nutritional supplement to complement surgery and chemoprevention in FAP.

Chemoprevention of intestinal adenomatous polyposis by acetyl-11-keto-beta-boswellic acid in APC(Min/+) mice.

Acetyl-11-keto-beta-boswellic acid (AKBA) is a derivative of boswellic acid, which is an active component of the gum resin of Boswellia serrata. AKBA has been used as an adjuvant medication for treatment of inflammatory diseases. In this study, we aimed to evaluate the efficacy of AKBA as a chemopreventive agent against intestinal adenomatous polyposis in the adenomatous polyposis coli multiple intestinal neoplasia (APC(Min/+) ) mouse model. APC(Min/+) mice were administered AKBA by p.o. gavage for 8 consecutive weeks. The mice were sacrificed and the number, size and histopathology of intestinal polyps were examined by light microscopy. AKBA decreased polyp numbers by 48.9% in the small intestine and 60.4% in the colon. An even greater AKBA effect was observed in preventing the malignant progression of these polyps. The number of large (>3 cm) colonic polyposis was reduced by 77.8%. Histopathologic analysis demonstrated a significant reduction in the number of dysplastic cells and in the degree of dysplasia in each polyp after AKBA treatment. There was no evidence of high grade dysplasia or intramucosal carcinoma in any of the polyps examined within the treated group. More interestingly, interdigitated normal appearing intestinal villi were observed in the polyps of the treated group. During the course of the study, AKBA was well tolerated by the mice with no obvious signs of toxicity. Results from immunohistochemical staining, Western blotting and enzyme-linked immunosorbent assay indicated that the chemopreventive effect of AKBA was attributed to a collection of activities including antiproliferation, apoptosis induction, antiangiogenesis and anti-inflammation. AKBA was found to exert its chemopreventive action through the inhibition of the Wnt/ß-catenin and NF-κB/cyclooxygenase-2 signaling pathways. Our findings suggest that AKBA could be a promising regimen in chemoprevention against intestinal tumorigenesis.

Macroscopic and histologic regression of duodenal polyposis with FOLFOX4 chemotherapy for an ileal pouch adenocarcinoma in a patient with familial adenomatous polyposis.

Severe (stage IV) duodenal polyposis is difficult to manage in patients with familial adenomatous polyposis (FAP), with no effective medical treatment, complex endoscopic treatment modalities, and a high morbidity and mortality from pancreaticoduodenectomy. We present the case of a 44-year-old woman with FAP, stage IV duodenal polyposis, and with an ileal pouch adenocarcinoma that required surgery and adjuvant chemotherapy. Her duodenal polyposis regressed to stage II after four sessions of FOLFOX4 adjuvant chemotherapy, which avoided the need for aggressive endoscopic therapy or pancreatoduodenectomy in this patient.

Papillary thyroid cancer in a patient with MUTYH-associated polyposis (MAP).

We describe a patient with MUTYH-associated polyposis diagnosed with colon cancer at 33 years of age, as well as gastric polyps at a later age. She was also diagnosed with papillary thyroid cancer at age 35. MUTYH-associated polyposis is an autosomal recessively inherited disease which has clinical overlap with Familial adenomatous polyposis and its attenuated form, in that it is associated with risk of colon cancer at a young age. Extra-intestinal cancers have also been reported in patients with MUTYH-associated polyposis; however the tumor spectrum is still evolving. National Comprehensive Cancer Network guidelines recommend screening for colon, duodenal and gastric polyps in individuals with MUTYH-associated polyposis. Screening for extra-intestinal cancers i.e. thyroid cancer is presently not part of these recommendations. These will likely continue to evolve as the MUTYH-associated polyposis tumor spectrum is better understood as a result of future case reports and research.

Dietary calcium and cholecalciferol modulate cyclin D1 expression, apoptosis, and tumorigenesis in intestine of adenomatous polyposis coli1638N/+ mice.

Both epidemiological and experimental findings have indicated that components of Western diets influence colonic tumorigenesis. Among dietary constituents, calcium and cholecalciferol have emerged as promising chemopreventive agents. We have demonstrated that a Western-style diet (WD) with low levels of calcium and cholecalciferol and high levels of (n-6) PUFA, increased the incidence of neoplasia in mouse intestine compared with a standard AIN-76A diet; models included wild-type mice and mice with targeted mutations. In the present study, adenomatous polyposis coli (Apc)(1638N/+) mice carrying a heterozygous Apc mutation were fed either an AIN-76A diet, a WD, or a WD supplemented with calcium and cholecalciferol (WD/Ca/VitD3). Diets were fed for 24 wk and effects on cellular and molecular events were assessed by performing immunohistochemistry in colonic epithelium along the crypt-to-surface continuum. Feeding WD to Apc(1638N/+) mice not only enhanced cyclin D1 expression in colonic epithelium compared with AIN-76A treatment as previously reported but also significantly increased the expression of the antiapoptotic protein B-cell lymphoma 2 (Bcl-2) concomitantly with a decrease in the proapoptotic Bcl2-associated X protein and the number of apoptotic epithelial cells. WD treatment enhanced mutant Apc-driven small intestinal carcinogenesis and also resulted in the formation of a small number of colonic adenomas (0.16 +/- 0.09; P < 0.05). By contrast, the WD/Ca/VitD3 diet reversed WD-induced growth, promoting changes in colonic epithelium. Importantly, Apc(1638N/+) mice fed the WD/Ca/VitD3 diet did not develop colonic tumors, further indicating that dietary calcium and cholecalciferol have a key role in the chemoprevention of colorectal neoplasia in this mouse model of human colon cancer.

Familial adenomatous polyposis complicated with an invasive colo-rectal adenocarcinoma in a 26-year-old Nigerian male - a rare finding.

Familial adenomatous polyposis is very rare in our environment. This condition occurring with a complication of a colorectal cancer has never been reported to the best of our knowledge. We present a case of a 26-year-old Nigerian man who came to us in February this year with a 10-year history of watery stool, which is also mucoid with tenesmus. There was also associated weight loss and colicky abdominal pains. He had also previously had a previous proctoscopy and rectal biopsy that showed numerous adenomatous polyps with dysplastic changes confirmed by histology. Barium enema revealed multiple polyps up to the right side of the transverse colon. Repeat histology after panproctocolectomy confirmed foci of invasive adenocarcinoma of the colon up to the muscle coat. The patient post-operatively is alive and well.

Conditional mouse models of cancer.

The development of inducible and conditional technologies allowed us to generate transgenic mouse models that faithfully recapitulate human tumorigenesis. It is possible to control, in time and space, the development of tumors in almost every mouse tissue. The result is that now we have available mouse models for all major human cancers. Novel noninvasive approaches to tumor imaging will enable us to follow tumor development and metastasis in vivo, as well as the effects of candidate therapeutic drugs. Such new generation tumor models, which accurately emulate the disease state in situ, should provide a useful platform with which to experimentally test drugs targeted to specific gene products, or combinations of genes that control rate-limiting steps of tumor development. In this review, we focus on the different mouse models for colon cancer.

Combination treatment with curcumin and quercetin of adenomas in familial adenomatous polyposis.

BACKGROUND & AIMS: Familialadenomatous polyposis (FAP) is an autosomal-dominant disorder characterized by the development of hundreds of colorectal adenomas and eventual colorectal cancer. Regression of adenomas in this syndrome occurs with the administration of nonsteroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors, but these compounds can have considerable side effects. We evaluated the efficacy of the combination of diet-derived nonprescription supplements curcumin and quercetin to regress adenomas in patients with FAP. METHODS: Five FAP patients with prior colectomy (4 with retained rectum and 1 with an ileal anal pouch) received curcumin 480 mg and quercetin 20 mg orally 3 times a day. The number and size of polyps were assessed at baseline and after therapy. The Wilcoxon signed-rank test was used to determine differences in the number and size of polyps. Treatment side effects and medication compliance also were evaluated. RESULTS: All 5 patients had a decreased polyp number and size from baseline after a mean of 6 months of treatment with curcumin and quercetin. The mean percent decrease in the number and size of polyps from baseline was 60.4% (P < .05) and 50.9% (P < .05), respectively. Minimal adverse side effects and no laboratory abnormalities were noted. CONCLUSIONS: The combination of curcumin and quercetin appears to reduce the number and size of ileal and rectal adenomas in patients with FAP without appreciable toxicity. Randomized controlled trials are needed to validate these findings.

Effect of the non-steroidal anti-inflammatory drug sulindac on colorectal adenomas of uncolectomized familial adenomatous polyposis.

BACKGROUND: The aim of the present study was to elucidate the effect of sulindac on uncolectomized familial adenomatous polyposis (FAP). METHODS: Seven FAP patients (SU group) without proctocolectomy were given sulindac 300 mg/day orally for 12 months. Six FAP patients without sulindac (non-SU group) served as controls. Colorectal lesions were assessed by protrusion index (no. radiolucent areas/cm(2); PI) under barium enema examination and non-polypoid lesion were assessed under chromoscopy prior to and at the end of the observation period. In the SU group, germline adenomatous polyposis coli (APC) mutation was determined by protein truncation test. RESULTS: In the SU group, PI decreased significantly in the distal colon (from 3.0 +/- 1.1 to 1.1 +/- 0.8/cm(2), P < 0.02) and in the proximal colon (from 3.4 +/- 2.4 to 0.9 +/- 1.3/cm(2), P < 0.02). The PI in the non-SU group slightly but significantly increased in the distal colon (from 1.0 +/- 0.8 to 1.2 +/- 0.9/cm(2); P < 0.05) and it remained unchanged in the proximal colon (from 0.6 +/- 0.3 to 0.7 +/- 0.3/cm(2); P > 0.05). Chromoscopy at the end of observation identified non-polypoid lesions in five patients in the SU group, whereas such lesions were not found in the non-SU group (71% vs 0%, P = 0.016). Decrease in PI was not different among distal APC mutation (exons 1-9), proximal APC mutation (exons 10-15) and negative mutation. CONCLUSION: Sulindac reduces colorectal adenomas of protruding type in uncolectomized FAP. The effect of sulindac may be unrelated to genotype of FAP.

[Treatment of Familial Adenomatous Polyposis and family screening]. / Poliposis familiar: alternativas terapéuticas y estudio de los familiares.

BACKGROUND: To reduce the mortality associated to Familial Adenomatous Polyposis (FAP), screening of close relatives of patients with the disease is crucial. AIM: To analyze the results of the surgical treatment of patients with FAP, and to evaluate the family screening. PATIENTS AND METHODS: Clinical records of patients operated in our institution since 1977, were reviewed analyzing surgical and pathological results, and follow up. In their family members, we evaluated and analyzed the performance of screening tests, former surgeries, history of disease-related cancer and mortality, all due to FAP. RESULTS: Between January 1977 and August 2002, 15 patients were operated on. Of these, only 33% consulted on the setting of a familial screening. A proctocolectomy and terminal ileostomy was performed in 27% of patients; 20% had a proctocolectomy and ileal pouch, and 53% underwent a total colectomy with ileo-rectal anastomosis. Morbidity and mortality were 7% and 0%, respectively. Twenty percent had a colorectal cancer. During a median of 68 months follow-up, the disease-related survival was 92%; no cancer of the rectal stump was detected. Of the 122 family members identified, only 33% with clear indication of screening underwent a colonoscopy. Twenty-nine percent had a confirmed FAP and were operated: in 61% of them a colorectal cancer was found, and 91% of these died. CONCLUSIONS: The results of the surgical treatment of FAP are satisfactory. Nevertheless, family screening should be improved to reduce the high rates of mortality revealed in the study of other family members.

Poliposis familiar: Alternativas terapéuticas y estudio de los familiares / Treatment of familial adenomatous polyposis and family screening

Background: To reduce the mortality associated to Familial Adenomatous Polyposis (FAP), screening of close relatives of patients with the disease is crucial. Aim: To analyze the results of the surgical treatment of patients with FAP, and to evaluate the family screening. Patients and Methods: Clinical records of patients operated in our institution since 1977, were reviewed analyzing surgical and pathological results, and follow up. In their family members, we evaluated and analyzed the performance of screening tests, former surgeries, history of disease-related cancer and mortality, all due to FAP. Results: Between January 1977 and August 2002, 15 patients were operated on. Of these, only 33 percent consulted on the setting of a familial screening. A proctocolectomy and terminal ileostomy was performed in 27 percent of patients; 20 percent had a proctocolectomy and ileal pouch, and 53 percent underwent a total colectomy with ileo-rectal anastomosis. Morbidity and mortality were 7 percent and 0 percent, respectively. Twenty percent had a colorectal cancer. During a median of 68 months follow-up, the disease-related survival was 92 percent; no cancer of the rectal stump was detected. Of the 122 family members identified, only 33 percent with clear indication of screening underwent a colonoscopy. Twenty-nine percent had a confirmed FAP and were operated: in 61 percent of them a colorectal cancer was found, and 91 percent of these died. Conclusions: The results of the surgical treatment of FAP are satisfactory. Nevertheless, family screening should be improved to reduce the high rates of mortality revealed in the study of other family members (Rev Méd Chile 2005; 133: 1043-50).

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.