Chemoprevention of colorectal cancer: a role for ursodeoxycholic acid, folate and hormone replacement treatment?

Is folic acid associated with lung cancer development? A cross-sectional study in NHANES

OBJECTIVE

The folic acid is used as an adjuvant dietary supplement in cancer treatment, but its potential benefits or adverse effects in lung cancer (LC) management remain unclear. This study aimed to examine the relationship between different forms of folic acid and LC based on a national population-based survey and conduct a thorough analysis of the potential use of folic acid in cancer treatment.

METHODS

Cross-sectional analysis from the 2007-2018 National Health and Nutrition Examination Survey (NHANES) was assessed. A cohort of 27,631 participants was identified and weighted. Information on folic acid levels and malignancy was determined through laboratory tests and interviews. To address potential confounding variables, a 1:2 propensity score matching (PSM) was employed, and 201 participants were included. This study utilized restricted cubic splines (RCS) to explore the none-linear relationship between various forms of folic acid and the incidence of LC.

RESULTS

Significant associations were observed between clinical characteristics of the participants and LC in both unweighted and weighted analyses. Following PSM, total folate, dietary folate, 5-formyltetrahydrofolate (5-formylTHF) and 5,10-methylenetetrahydrofolate (5,10-methenylTHF) were significantly associated with LC risk (p < 0.05). The RCS analysis suggested that there was a significant non-linear association between 5,10-methenylTHF and the odds of developing LC. Additionally, total folate, folic acid, 5,10-methenylTHF, and RBC folate influenced the likelihood of developing LC in a certain dose range.

CONCLUSIONS

The development of LC was associated with total folate, dietary folate, 5-formylTHF and 5,10-methenylTHF levels. Folic acid, total folate, 5,10-methenylTHF, and RBC folate were positively correlated with LC within a certain range.

Estrogen receptor beta expression in colitis-associated carcinoma in comparison with sporadic colonic tumor: An immunohistochemical study

Background and Aim

The rate of ulcerative colitis (UC)-related colorectal cancer (colitis-associated carcinoma) is increasing. Estrogen receptor (ER) beta expression has been studied separately in patients with sporadic colorectal cancer and those with colitis-associated carcinoma. However, no study has compared the expression in both of these cancer types. The present study aimed to evaluate the relationship between colitis-associated carcinoma and ERs and assess whether the expression of ER beta influences cell proliferation.

Methods

This study included 45 surgically operated colitis-associated carcinomas, 43 high-grade dysplasias, 34 low-grade dysplasias, 36 sporadic colorectal cancers, 44 high-grade adenomas, and 34 low-grade adenomas. ER beta expression was evaluated with immunohistochemistry.

Results

Colitis-associated carcinoma showed significantly lower ER beta immunoexpression than sporadic colorectal lesions and high- and low-grade dysplasia. In seven colitis-associated carcinoma harboring both intensity score 3 (strong immunoexpression) and score 1 (weak immunoexpression) areas, the correlation among ER beta intensity, Ki-67, and p21 labeling index was assessed; an area with an ER beta intensity score of 3 showed a higher Ki-67 labeling index than that with score 1. In four out of the seven lesions, p21 labeling index was higher in the area of ER beta score 1 than in that of ER beta score 3.

Conclusions

The data suggest that ER beta expression is an accelerating factor in colorectal tumors. This association may be lower in colitis-associated carcinoma than in sporadic colorectal cancer.

Cervical Cancer, Different Treatments and Importance of Bile Acids as Therapeutic Agents in This Disease

Cervical cancer can be cured, because it has a long preinvasive period. Early diagnosis and treatment of cervical cancer at women are crucial for reducing of rate mortality. Today, there are many methods for detecting premalignant lesions and one of them is a conventional Papanicolaou test. Cervical cancer develops through a series of changes in the epithelium called cervical intraepithelial neoplasia (CIN). The biological and genetic characteristics of the cells at cancer in situ are irreversibly altered and abnormal cells have the potential to metastasize to others anatomical regions. Infection with human Papillomavirus, which is transmitted sexually, is considered the main cause and represent the necessary, but not the only factor for the development of cervical cancer. Types of high risk human Papillomavirus are often associated with invasive cervical cancer. The carcinogenic types of HPV 16 and 18 are responsible for 70% of cervical cancer and about 50% of CIN 3. Primary prevention of cervical cancer is aimed at reducing incidence, control of causes and risk factors. In this scientific work, in addition to explaining the various treatments necessary for the treatment of cervical carcinoma, we were discussed about the anticancer effects of the synthetic derivative of ursodeoxycholic acid, such as HS-1183, and synthetic derivatives of chenodeoxycholic acid such as HS-1199 and HS-1200. Also, the effects of bile acid complexes with metals such as platinum, zinc, nickel, and copper were considered in the effective treatment of cervical cancer. KEY POINTS • Lymphogenic spreading of cervical cancer occurs relatively early in the regional lymph nodes, while this sort of progression of cervical cancer is rarer in the juxtaregional (paraaortic), mediastinal and supraclavicular nodes. Clinically proven supraclavicular metastases are not a rarity. In stages IIb and IIIa with metastases in paraaortal nodes occur a 20% metastases at the neck lymph nodes. Hematogenic metastases are relatively rare and occur in the posterior phase. Distant metastases are detected in the lungs and liver. Preinvasive and microinvasive stages of cervical cancer are without symptoms. With deeper invasion of the strome, certain clinical symptoms such as prolonged menstruation, increased vaginal secretions, vaginal bleeding between the two periods, contact bleeding (after coitus), unilateral pelvic pain with spreading in hip joint (infiltration of the pelvic nerve plexus), dysuric disturbance, anemia, islet of the lower extremities. In order to diagnose the level spreading of primary lesion of cervical cancer most commonly are used the supplemental searches such as cytoscopy, rectoscopy, urography, irigography, lung and bone radiography, scintigraphy of the liver, kidney and bone, lymphography, CT (MR) of abdomen and pelvis, as well as laboratory analysis. Surgical treatment consists of transvaginal hysterectomy, transabdominal removal of the uterus (via laparotomy), bilateral adenectomy (removal of the ovaries and the fallopian tubes), upper and middle third of the vagina and lymphonodectomy of the regional lymph nodes. The most commonly used radiotherapy, intracavitary brachytherapy, manual afterloading technique and remote afterloading techniques. The synthetic derivatives of ursodeoxycholic acid and chenodeoxycholic acid such as HS-1183, HS-1199, and HS-1200 are used to treat cervical cancer. These derivatives of chenodeoxycholic acid and ursodeoxycholic acid are capable of inhibiting cell proliferation and inducing apoptosis in SiHa human cells of cervix. Platinum compounds are used as catalysts in cervical cancer therapy. Clinical use of platinum complexes for which the bile acids bind is based on the desire to achieve the death of tumor cells and the spectrum of drug activity in the treatment of cervical cancer. Bisursodeoxycholate (ethylenediamine) platinum (II) [Pt(UDC)2(en)] is characterized by important cytotoxicity against HeLa cervical carcinoma cells and this effect already being clearly detectable after 24 h.

Tauroursodeoxycholic acid attenuates colitis-associated colon cancer by inhibiting nuclear factor kappaB signaling

BACKGROUND AND AIM

Inflammatory bowel diseases is associated with an increased risk for the development of colorectal cancer. However, the mechanism of immune signaling pathways linked to colitis-associated cancer (CAC) has not been fully elucidated. Tauroursodeoxycholic acid (TUDCA) exhibits anti-inflammatory and anti-cancer activities. The aim of this study is to investigate the role of TUDCA in the pathogenesis of CAC.

METHODS

Colitis-associated cancer was induced in mice using azoxymethane and dextran sodium sulfate administration, and TUDCA's effect on tumor development was evaluated. HCT 116 and COLO 205 were treated with TUDCA or vehicle and then stimulated with tumor necrosis factor-α (TNF-α). Expression of interleukin (IL)-8 was determined by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, and IκBα phosphorylation and degradation was evaluated by immunoblot assay. The DNA-binding activity of NF-κB was assessed by electrophoretic mobility shift assay. Cell viability assay and real-time reverse transcription-polymerase chain reaction of bcl-xL, MCL1, c-FLIP-L, and VEGF were performed.

RESULTS

Tauroursodeoxycholic acid significantly attenuated the development of CAC in mice. Exposure to TUDCA resulted in extensive epithelial apoptosis and reduced levels of phospho-IκB kinase in the colon. In HCT 116 cells stimulated with TNF-α, TUDCA significantly inhibited IL-8 and IL-1α expression and suppressed TNF-α-induced IκBα phosphorylation/degradation and DNA-binding activity of NF-κB. Furthermore, in both HCT 116 and COLO 205 cells, TUDCA reduced cell viability and downregulated the expression of bcl-xL, MCL1, c-FLIP-L, and VEGF.

CONCLUSION

These results demonstrated that TUDCA suppresses NF-κB signaling and ameliorates colitis-associated tumorigenesis, suggesting that TUDCA could be a potential treatment for CAC.

Reviewing the Risk of Colorectal Cancer in Inflammatory Bowel Disease After Liver Transplantation for Primary Sclerosing Cholangitis

The presence of concomitant primary sclerosing cholangitis (PSC) with inflammatory bowel disease (IBD) represents a distinct disease phenotype that carries a higher risk of colorectal cancer (CRC) than the average IBD patient. Given that liver transplantation (LT) is the only treatment that offers a survival benefit in PSC patients with hepatic dysfunction, management decisions in IBD patients' post-LT for PSC are frequently encountered. One such consideration is the risk of CRC in this immunosuppressed cohort. With most studies showing an increased risk of CRC post-LT in these IBD patients, a closer look at the associated risk factors of CRC and the adopted surveillance strategies in this subset of patients is warranted. Low-dose ursodeoxycholic acid has shown a potential chemopreventive effect in PSC-IBD patients pre-LT; however, a favorable effect remains to be seen in post-LT group. Also, further studies are necessary to assess the benefit of 5 aminosalicylate therapy. Annual surveillance colonoscopy in the post-LT period is recommended for PSC-IBD patients subset given their high risk for CRC.

Prevention of Colorectal Neoplasia

Colorectal cancer (CRC) is one of the leading causes of cancer-related morbidity and mortality worldwide. There are well-established screening protocols involving fecal testing, radiographic, and endoscopic evaluations that have led to decreased incidence and mortality of CRC in the United States. In addition to screening for CRC, there is interest in preventing colorectal neoplasia by targeting the signaling pathways that have been identified in the pathway of dysplasia progressing to carcinoma. This review will detail the efficacy of multiple potential preventative strategies including lifestyle changes (physical activity, alcohol use, smoking cessation, and obesity); dietary factors (dietary patterns, calcium, vitamin D, fiber, folate, and antioxidants and micronutrients); and chemopreventive agents (nonsteroidal anti-inflammatory drugs, statins, metformin, bisphosphonates, and postmenopausal hormonal therapy).

Chemoprevention of colorectal neoplasia

BACKGROUND

Colorectal cancer is a common and often fatal malignancy. Currently, the modifications that alter disease outcome include early symptom recognition, population screening as well as improved surgical and adjuvant treatments. Preventative strategies have been limited with little evidence that lifestyle changes significantly alter risk. There is however a growing awareness of a potential role for chemoprevention in some patient groups. This study aimed to review the literature associated with chemoprevention in colorectal cancer.

METHODS

An electronic literature search of MEDLINE and Embase databases was performed on PubMed for studies detailing the use of chemoprevention agents in colon and rectal cancer. The search was limited to clinical trials on adult humans (>16 years of age) published in English since 1990.

RESULTS

The strongest evidence is for non-steroidal anti-inflammatory drugs slowing polyp progression, notably Sulindac and aspirin in patients with familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, respectively. There is also increasing evidence that continuing use of low-dose aspirin reduces long-term incidence of colorectal cancers. Cyclooxygenase 2 inhibitors also have a potential role but cardiac toxicity currently limits their use. Folic acid, statins, antioxidants, calcium and 5-aminosalicylic acid lack evidence to support their use at present.

CONCLUSIONS

Currently, there is not enough evidence to support the implementation of a chemopreventative agent for general use. However, there appears to be a role for aspirin in selected subgroups.

Prognosis of Ulcerative Colitis-Associated Colorectal Carcinoma Compared to Sporadic Colorectal Carcinoma: A Matched Pair Analysis

BACKGROUND

Ulcerative colitis (UC) patients have an increased risk of developing colorectal carcinoma (CRC). In contrast to clinical and pathogenetic differences, little is known about how prognosis compares between these patients and those with sporadic CRC. The aim of this study was to compare their characteristics and prognosis and identify independent risk factors for patients with UC-associated CRC.

METHODS

A total of 126 patients who underwent surgery in our department (1984-2010) for UC-associated (n = 63) or sporadic (n = 63) CRC were included in this analysis. Patients were matched according to sex, tumor location, and disease stage. Clinical parameters and overall, recurrence-free, and disease-specific survival were compared. In subgroup analyses, clinical parameters of UC patients were correlated with survival.

RESULTS

Median follow-up was 129 months in the UC group and 99 months in the sporadic CRC group. UC patients were significantly younger and had more multifocal, high-grade, and mucinous carcinomas. Five-year overall survival rate for UC-associated and sporadic CRC was similar (65.7 vs. 63.2%, p = 0.98). Recurrence-free survival for International Union Against Cancer (UICC) stage II disease was superior in the sporadic CRC group (p = 0.039). In a subgroup analysis of UC patients, a shorter duration of UC (p = 0.045) and male sex (p = 0.005) were associated with a worse prognosis.

CONCLUSIONS

Despite multiple clinical and histopathologic differences between UC-associated and sporadic CRC patients, overall survival and disease-specific survival are similar. In a subgroup analysis of UC patients with CRC, female sex was associated with a significantly better prognosis. This finding implies that estrogens may play a protective role in UC-associated CRC carcinogenesis.

Ulcerative colitis: from inflammation to cancer. Do estrogen receptors have a role?

Ulcerative colitis (UC) is a condition at increased risk for colorectal carcinoma (CRC) development. Nowadays, screening and follow-up programs are routinely performed worldwide to promote the early detection of CRCs in subjects with well known risk factors (extent, duration and severity of the disorder). The diffusion of these procedures is presumably the main reason for the marked reduction of cancer incidence and mortality in the course of UC. In addition, chemoprevention has been widely investigated and developed in many medical fields, and aspirin has shown a preventive effect against CRC, while mesalazine has been strongly invoked as a potential chemopreventive agent in UC. However, available studies show some limitations due to the obvious ethical implications of drug withdrawal in UC in order to design a control group. The estrogen receptors (ER) alpha/beta balance seems to have a relevant influence on colorectal carcinogenesis and ER beta appears to parallel apoptosis, and hence an anti-carcinogenic effect. Phytoestrogens are compounds acting as ER beta agonists and have shown a promising chemopreventive effect on sporadic as well as genetically inherited CRC. There is evidence suggesting a role for ERs in UC-related carcinogenesis. In this perspective, since these substances can be considered as dietary supplements and are completely free from side effects, phytoestrogens could be an interesting option for CRC prevention, even when the disease is a consequence of long-term chronic inflammation, as in the course of UC. Further studies of their effects are warranted in both the basic research and clinical fields.

Eicosapentaenoic acid free fatty acid prevents and suppresses colonic neoplasia in colitis-associated colorectal cancer acting on Notch signaling and gut microbiota

Inflammatory bowel diseases are associated with increased risk of developing colitis-associated colorectal cancer (CAC). Epidemiological data show that the consumption of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) decreases the risk of sporadic colorectal cancer (CRC). Importantly, recent data have shown that eicosapentaenoic acid-free fatty acid (EPA-FFA) reduces polyp formation and growth in models of familial adenomatous polyposis. However, the effects of dietary EPA-FFA are unknown in CAC. We tested the effectiveness of substituting EPA-FFA, for other dietary fats, in preventing inflammation and cancer in the AOM-DSS model of CAC. The AOM-DSS protocols were designed to evaluate the effect of EPA-FFA on both initiation and promotion of carcinogenesis. We found that EPA-FFA diet strongly decreased tumor multiplicity, incidence and maximum tumor size in the promotion and initiation arms. Moreover EPA-FFA, in particular in the initiation arm, led to reduced cell proliferation and nuclear β-catenin expression, whilst it increased apoptosis. In both arms, EPA-FFA treatment led to increased membrane switch from ω-6 to ω-3 PUFAs and a concomitant reduction in PGE2 production. We observed no significant changes in intestinal inflammation between EPA-FFA treated arms and AOM-DSS controls. Importantly, we found that EPA-FFA treatment restored the loss of Notch signaling found in the AOM-DSS control and resulted in the enrichment of Lactobacillus species in the gut microbiota. Taken together, our data suggest that EPA-FFA is an excellent candidate for CRC chemoprevention in CAC.

5-methyl-tetrahydrofolate and the S-adenosylmethionine cycle in C57BL/6J mouse tissues: gender differences and effects of arylamine N-acetyltransferase-1 deletion

Folate catabolism involves cleavage of the C⁹-N¹⁰ bond to form p-aminobenzoylgluamate (PABG) and pterin. PABG is then acetylated by human arylamine N-acetyltransferase 1 (NAT1) before excretion in the urine. Mice null for the murine NAT1 homolog (Nat2) show several phenotypes consistent with altered folate homeostasis. However, the exact role of Nat2 in the folate pathway in vivo has not been reported. Here, we examined the effects of Nat2 deletion in male and female mice on the tissue levels of 5-methyl-tetrahydrofolate and the methionine-S-adenosylmethionine cycle. We found significant gender differences in hepatic and renal homocysteine, S-adenosylmethionine and methionine levels consistent with a more active methionine-S-adenosylmethionine cycle in female tissues. In addition, methionine levels were significantly higher in female liver and kidney. PABG was higher in female liver tissue but lower in kidney compared to male tissues. In addition, qPCR of mRNA extracted from liver tissue suggested a significantly lower level of Nat2 expression in female animals. Deletion of Nat2 affected liver 5- methyl-tetrahydrofolate in female mice but had little effect on other components of the methionine-S-adenosylmethionine cycle. No N-acetyl-PABG was observed in any tissues in Nat2 null mice, consistent with the role of Nat2 in PABG acetylation. Surprisingly, tissue PABG levels were similar between wild type and Nat2 null mice. These results show that Nat2 is not required to maintain tissue PABG homeostasis in vivo under normal conditions.

Phytoestrogens/insoluble fibers and colonic estrogen receptor β: randomized, double-blind, placebo-controlled study

AIM

To assess the safety and effect of the supplementation of a patented blend of dietary phytoestrogens and insoluble fibers on estrogen receptor (ER)-β and biological parameters in sporadic colonic adenomas.

METHODS

A randomized, double-blind placebo-controlled trial was performed. Patients scheduled to undergo surveillance colonoscopy for previous sporadic colonic adenomas were identified, and 60 eligible patients were randomized to placebo or active dietary intervention (ADI) twice a day, for 60 d before surveillance colonoscopy. ADI was a mixture of 175 mg milk thistle extract, 20 mg secoisolariciresinol and 750 mg oat fiber extract. ER-β and ER-α expression, apoptosis and proliferation (Ki-67 LI) were assessed in colon samples.

RESULTS

No adverse event related to ADI was recorded. ADI administration showed a significant increases in ER-β protein (0.822 ± 0.08 vs 0.768 ± 0.10, P = 0.04) and a general trend to an increase in ER-β LI (39.222 ± 2.69 vs 37.708 ± 5.31, P = 0.06), ER-β/ER-α LI ratio (6.564 ± 10.04 vs 2.437 ± 1.53, P = 0.06), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (35.592 ± 14.97 vs 31.541 ± 11.54, P = 0.07) and Ki-67 (53.923 ± 20.91 vs 44.833 ± 10.38, P = 0.07) approximating statistical significance. A significant increase of ER-β protein (0.805 ± 0.13 vs 0.773 ± 0.13, P = 0.04), mRNA (2.278 ± 1.19 vs 1.105 ± 1.07, P < 0.02) and LI (47.533 ± 15.47 vs 34.875 ± 16.67, P < 0.05) and a decrease of ER-α protein (0.423 ± 0.06 vs 0.532 ± 0.11, P < 0.02) as well as a trend to increase of ER-β/ER-α protein in ADI vs placebo group were observed in patients without polyps (1.734 ± 0.20 vs 1.571 ± 0.42, P = 0.07).

CONCLUSION

The role of ER-β on the control of apoptosis, and its amenability to dietary intervention, are supported in our study.

Ursodeoxycholic acid-conjugated chitosan for photodynamic treatment of HuCC-T1 human cholangiocarcinoma cells

Chitosan was hydrophobically modified with ursodeoxycholic acid (UDCA) to fabricate nano-photosensitizer for photodynamic therapy (PDT) of HuCC-T1 cholangiocarcinoma cells. Synthesis of UDCA-conjugated chitosan (ChitoUDCA) was confirmed using (1)H NMR spectra. Chlorin E6 (Ce6) was used as a photosensitizer and incorporated into ChitoUDCA nanoparticles through formation of ion complexes. Morphology of Ce6-incorporated ChitoUDCA nanoparticles was observed using TEM and their shapes were spherical with sizes around 200-400 nm. The PDT potential of Ce6-incorporated ChitoUDCA nanoparticles were studied with HuCC-T1 human cholangiocarcinoma cells. The results showed that ChitoUDCA nanoparticles enhances of Ce6 uptake into tumor cells, phototoxicity, and ROS generation compared to Ce6 itself. Furthermore, Ce6-incorporated ChitoUDCA nanoparticles showed quenching in aqueous solution and sensing at tumor cells. We suggest that Ce6-incorporated ChitoUDCA nanoparticles are promising candidates for PDT of cholangiocarcinoma cells.

The unfolded protein response and chemical chaperones reduce protein misfolding and colitis in mice

BACKGROUND & AIMS

Endoplasmic reticulum (ER) stress has been associated with development of inflammatory bowel disease. We examined the effects of ER stress-induced chaperone response and the orally active chemical chaperones tauroursodeoxycholate (TUDCA) and 4-phenylbutyrate (PBA), which facilitate protein folding and reduce ER stress, in mice with colitis.

METHODS

We used dextran sulfate sodium (DSS) to induce colitis in mice that do not express the transcription factor ATF6α or the protein chaperone P58(IPK). We examined the effects of TUDCA and PBA in cultured intestinal epithelial cells (IECs); in wild-type, P58(IPK-/-), and Atf6α(-/-) mice with colitis; and in Il10(-/-) mice.

RESULTS

P58(IPK-/-) and Atf6α(-/-) mice developed more severe colitis following administration of DSS than wild-type mice. IECs from P58(IPK-/-) mice had excessive ER stress, and apoptotic signaling was activated in IECs from Atf6α(-/-) mice. Inflammatory stimuli induced ER stress signals in cultured IECs, which were reduced by incubation with TUDCA or PBA. Oral administration of either PBA or TUDCA reduced features of DSS-induced acute and chronic colitis in wild-type mice, the colitis that develops in Il10(-/-) mice, and DSS-induced colitis in P58(IPK-/-) and Atf6α(-/-) mice. Reduced signs of colonic inflammation in these mice were associated with significantly decreased ER stress in colonic epithelial cells.

CONCLUSIONS

The unfolded protein response induces expression of genes that encode chaperones involved in ER protein folding; these factors prevent induction of colitis in mice. Chemical chaperones such as TUDCA and PBA alleviate different forms of colitis in mice and might be developed for treatment of inflammatory bowel diseases.

Bile acids in the colon, from healthy to cytotoxic molecules

Bile acids are natural detergents mainly involved in facilitating the absorption of dietary fat in the intestine. In addition to this absorptive function, bile acids are also essential in the maintenance of the intestinal epithelium homeostasis. To accomplish this regulatory function, bile acids may induce programmed cell death fostering the renewal of the epithelium. Here we first discuss on the different molecular pathways of cell death focusing on apoptosis in colon epithelial cells. Bile acids may induce apoptosis in colonocytes through different mechanisms. In contrast to hepatocytes, the extrinsic apoptotic pathway seems to have a low relevance regarding bile acid cytotoxicity in the colon. On the contrary, these molecules mainly trigger apoptosis through direct or indirect mitochondrial perturbations, where oxidative stress plays a key role. In addition, bile acids may also act as regulatory molecules involved in different cell signaling pathways in colon cells. On the other hand, there is increasing evidence that the continuous exposure to certain hydrophobic bile acids, due to a fat-rich diet or pathological conditions, may induce oxidative DNA damage that, in turn, may lead to colorectal carcinogenesis as a consequence of the appearance of cell populations resistant to bile acid-induced apoptosis. Finally, some bile acids, such as UDCA, or low concentrations of hydrophobic bile acids, can protect colon cells against apoptosis induced by high concentrations of cytotoxic bile acids, suggesting a dual behavior of these agents as pro-death or pro-survival molecules.

Estrogen plus progestin and colorectal cancer incidence and mortality

PURPOSE

During the intervention phase in the Women's Health Initiative (WHI) clinical trial, use of estrogen plus progestin reduced the colorectal cancer diagnosis rate, but the cancers were found at a substantially higher stage. To assess the clinical relevance of the findings, analyses of the influence of combined hormone therapy on colorectal cancer incidence and colorectal cancer mortality were conducted after extended follow-up.

PATIENTS AND METHODS

The WHI study was a randomized, double-blind, placebo-controlled clinical trial involving 16,608 postmenopausal women with an intact uterus who were randomly assigned to daily 0.625 mg conjugated equine estrogen plus 2.5 mg medroxyprogesterone acetate (n = 8,506) or matching placebo (n = 8,102). Colorectal cancer diagnosis rates and colorectal cancer mortality were assessed.

RESULTS

After a mean of 5.6 years (standard deviation [SD], 1.03 years) of intervention and 11.6 years (SD, 3.1 years) of total follow-up, fewer colorectal cancers were diagnosed in the combined hormone therapy group compared with the placebo group (diagnoses/year, 0.12% v 0.16%; hazard ratio [HR], 0.72; 95% CI, 0.56 to 0.94; P = .014). Bowel screening examinations were comparable between groups throughout. Cancers in the combined hormone therapy group more commonly had positive lymph nodes (50.5% v 28.6%; P < .001) and were at higher stage (regional or distant, 68.8% v 51.4%; P = .003). Although not statistically significant, there was a higher number of colorectal cancer deaths in the combined hormone therapy group (37 v 27 deaths; 0.04% v 0.03%; HR, 1.29; 95% CI, 0.78 to 2.11; P = .320).

CONCLUSION

The findings, suggestive of diagnostic delay, do not support a clinically meaningful benefit for combined hormone therapy on colorectal cancer.