HLA-DQA1*05 Allele Carriage and Anti-TNF Therapy Persistence in Inflammatory Bowel Disease.

INTRODUCTION: Carriage of the HLA-DQA1*05 allele is associated with development of antidrug antibodies (ADAs) to antitumor necrosis factor (anti-TNF) therapy in patients with Crohn's disease. However, ADA is not uniformly associated with treatment failure. We aimed to determine the impact of carriage of HLA-DQA1*05 allele on outcome of biologic therapy evaluated by drug persistence. METHODS: A multicenter, retrospective study of 877 patients with inflammatory bowel disease (IBD) treated with anti-TNF therapy with HLA-DQA1*05 genotypes were generated by imputation from whole genome sequence using the HIBAG package, in R. Primary end point was anti-TNF therapy persistence, (time to therapy failure), segregated by HLA-DQA1*05 allele genotype and development of a risk score to predict anti-TNF therapy failure, incorporating HLA-DQA1*05 allele genotype status (LORisk score). RESULTS: In all, 877 patients receiving anti-TNF therapy were included in our study; 543 (62%) had no copy, 281 (32%) one copy, and 53 (6%) 2 copies of HLA-DQA1*05 allele. Mean time to anti-TNF therapy failure in patients with 2 copies of HLA-DQA1*05 allele was significantly shorter compared with patients with 0 or 1 copy at 700 days' follow-up: 418 vs 541 vs 513 days, respectively (P = .012). Factors independently associated with time to anti-TNF therapy failure included carriage of HLA-DQA1*05 allele (hazard ratio [HR], 1.2, P = .02; female gender HR, 1.6, P < .001; UC phenotype HR, 1.4, P = .009; and anti-TNF therapy type [infliximab], HR, 1.5, P = .002). The LORisk score was significantly associated with shorter time to anti-TNF therapy failure (P < .001). CONCLUSIONS: Carriage of 2 HLA-DQA1*05 alleles is associated with less favorable outcomes for patients receiving anti-TNF therapy with shorter time to therapy failure. HLA-DQA1*05 genotype status in conjunction with clinical factors may aid in therapy selection in patients with IBD.

Our study found carriage of 2 copies of the HLA-DQA1*05 allele is associated with a less favorable response to anti-TNF therapy with shorter time to therapy failure. HLA-DQA1*05 genotype status in conjunction with clinical factors may aid in therapy selection in IBD patients.

Inflammatory Bowel Disease Disability Index is a valid and reliable measure of disability in an English-speaking hospital practice and predicts long-term requirement for treatment escalation.

Objective: The Inflammatory Bowel Disease Disability Index (IBD-DI) was developed according to WHO standards and has been validated in population-based cohorts. However, there are limited data on its relationship to various psychosocial and economic variables or its relevance to hospital clinical practice. The study aims were to determine the validity and reliability of the IBD-DI in an English-speaking hospital out-patient population and to evaluate its association with short and long-term disease activity. Design/Methods: 329 subjects were enrolled in a cross-sectional and longitudinal study assessing the IBD-DI and a range of quality of life, work impairment, depression, anxiety, body image, interpersonal, self-esteem, disease activity, symptom scoring scales in addition to long-term outcome. Results: The IBD-DI had adequate structure, was internally consistent and demonstrated convergent and predictive validity and was reliable in test-retest study. Disability was related to female sex (p=0.002), antidepressant use (p<0.001), steroid use (p<0.001) and disease activity (p<0.001). Higher IBD-DI scores were associated with long-term disease activity and need for treatment escalation in univariate (p<0.001) and multivariate (p=0.002) analyses. Conclusion: The IBD-DI is a valid and reliable measure of disability in English-speaking hospital populations and predicts long-term requirement for treatment escalation.

Implementation of BSG/ACPGBI/PHE polypectomy surveillance guidelines safely reduces the burden of surveillance in a screening cohort: a virtual model study.

OBJECTIVE: To evaluate the impact of British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland/Public Health England (BSG/ACPGBI/PHE) 2019 polypectomy surveillance guidelines within a national faecal immunochemical test-based bowel cancer screening (BS) cohort on surveillance activity and detection of pathology by retrospective virtual application. DESIGN: A retrospective review of BS colonoscopies performed in 2015-2016 with 5 years prospective follow-up in single institution. Index colonoscopies were selected. Incomplete colonoscopies were excluded. Histology of all resected polyps was reviewed. Surveillance intervals were calculated according to BSG/ACPGBI/PHE 2019 guidelines and compared with pre-existing 'European Guidelines for Quality Assurance in Colorectal Cancer Screening and Diagnosis' (EUQA 2013). Total number of colonoscopies deferred by virtual implementation of BSG/ACPGBI/PHE 2019 guidelines were calculated. Pathology identified on procedures that would have been deferred was reviewed. RESULTS: Total number of index BS colonoscopies performed in 2015-2016 inclusive was 890. 115 were excluded (22 no caecal intubation, 51 inadequate bowel preparation, 56 incomplete polyp clearance). N=509 colonoscopies were scheduled within a 5-year interval following index colonoscopy surveillance rounds based on EUQA guidelines. Overall, volume of surveillance was significantly reduced with retrospective application of BSG/ACPGBI/PHE 2019 guidelines (n=221, p<0.0001). No cancers were detected within the 'potentially deferred' procedures who attended for follow-up (n=330) with high-risk findings found in<10% (n=30) of colonoscopies within the BSG/ACPGBI/PHE cohort. CONCLUSION: BSG/ACPGBI/PHE 2019 guidelines safely reduce the burden of colonoscopy demand with acceptable pathology findings on deferred colonoscopies.

Reduced Serological Response to COVID-19 Booster Vaccine is Associated with Reduced B Cell Memory in Patients With Inflammatory Bowel Disease; VARIATION [VAriability in Response in IBD AgainsT SARS-COV-2 ImmunisatiON].

BACKGROUND AND AIMS: Patients with inflammatory bowel disease [IBD] have an attenuated response to initial COVID-19 vaccination. We sought to characterize the impact of IBD and its treatment on responses after the third vaccine against SARS-CoV-2. METHODS: This was a prospective multicentre observational study of patients with IBD [n = 202] and healthy controls [HC, n = 92]. Serological response to vaccination was assessed by quantification of anti-spike protein [SP] immunoglobulin [Ig]G levels [anti-SPIgG] and in vitro neutralization of binding to angiotensin-converting enzyme 2 [ACE2]. Peripheral blood B-cell phenotype populations were assessed by flow cytometry. SARS-CoV-2 antigen-specific B-cell responses were assessed in ex vivo culture. RESULTS: Median anti-SP IgG post-third vaccination in our IBD cohort was significantly lower than HCs [7862 vs 19 622 AU/mL, p < 0.001] as was ACE2 binding inhibition [p < 0.001]. IBD patients previously infected with COVID-19 [30%] had similar quantitative antibody response as HCs previously infected with COVID-19 [p = 0.12]. Lowest anti-SP IgG titres and neutralization were seen in IBD patients on anti-tumour necrosis factor [anti-TNF] agents, without prior COVID-19 infection, but all IBD patients show an attenuated vaccine response compared to HCs. Patients with IBD have reduced memory B-cell populations and attenuated B-cell responses to SARS-CoV-2 antigens if not previously infected with COVID-19 [p = 0.01]. Higher anti-TNF drug levels and zinc levels <65 ng/ml were associated with significantly lower serological responses. CONCLUSIONS: Patients with IBD have an attenuated response to three doses of SARS-CoV-2 vaccine. Physicians should consider patients with higher anti-TNF drug levels and/or zinc deficiency as potentially at higher risk of attenuated response to vaccination.

Reduced Serological Response to COVID-19 Vaccines in Patients with IBD is Further Diminished by TNF Inhibitor Therapy; Early Results of the VARIATION study [VAriability in Response in IBD Against SARS-COV-2 ImmunisatiON].

BACKGROUND AND AIMS: Evidence suggests patients with inflammatory bowel disease [IBD] receiving TNF antagonists have attenuated response to vaccination against COVID-19. We sought to determine the impact of IBD and of various medications for treatment of IBD on antibody responses to vaccination against COVID-19. METHODS: Patients with IBD [n = 270] and healthy controls [HC, n = 116] were recruited prospectively, and quantitative antibody responses were assessed following COVID-19 vaccination. The impact of IBD and of medications for treatment of IBD on vaccine response rates was investigated. RESULTS: Of HC, 100% seroconverted following complete vaccination with two vaccine doses; 2% of patients with IBD failed to seroconvert. Median anti-spike protein [SP] immunoglobulin [Ig]G levels following complete vaccination in our IBD cohort was significantly lower than among HC [2613 AU/mL versus 6871 AU/mL, p ≤0.001]. A diagnosis of IBD was independently associated with lower anti-SP IgG levels [ß coefficient -0.2, p = 0.001]. Use of mRNA vaccines was independently associated with higher anti-SP IgG levels [ß coefficient 0.25, p ≤0.001]. Patients with IBD receiving TNF inhibitors had significantly lower anti-SP IgG levels [2445 AU/mL] than IBD patients not receiving TNF inhibitors [3868 AU/mL, p ≤0.001]. Patients with IBD not receiving TNF inhibitors still showed attenuated responses compared with HC [3868 AU/mL versus 8747 AU/mL, p = 0.001]. CONCLUSIONS: Patients with IBD have attenuated serological responses to SARS-CoV-2 vaccination. Use of anti-TNF therapy negatively affects anti-SP IgG levels further. Patients who do not seroconvert following vaccination are a particularly vulnerable cohort. Impaired responses to vaccination in our study highlight the importance of booster vaccination programmes for patients with IBD.

Comparison of medium to long-term outcomes of acute severe ulcerative colitis patients receiving accelerated and standard infliximab induction.

INTRODUCTION: Accelerated dose infliximab (IFX) induction is associated with reduced short-term colectomy rate in acute severe ulcerative colitis (ASUC). Data on medium/long-term outcomes of this strategy are limited. AIMS: Evaluate medium/long-term outcomes in patients receiving IFX induction for ASUC, comparing accelerated dose (AD) and standard dose (SD) induction. METHODS: Retrospective study of consecutive patients admitted with corticosteroid-refractory ASUC in four tertiary referral centres within INITIative IBD research network (www.initiativeibd.ie). IFX rescue was given either as SD (weeks 0, 2, 6) or AD (<28 days) from January 2010 to September 2017. AD induction has been utilised in participating centres since 2014. Consequently SD patients were subdivided based on time period of IFX rescue: historical SD group (SD1) (2010-2013) and current SD group (SD2) (2014-2017). Primary endpoint was time to colectomy; secondary endpoint was time to IFX discontinuation if induction was complete. RESULTS: 145 patients received rescue IFX (AD=58, SD1=32, SD2=55). Disease severity at induction was comparable between AD and SD1 groups; however, SD2 group had less severe disease: median C-reactive protein (CRP) 39, 44 and 20 mg/L for AD, SD1 and SD2 groups, respectively (p=0.026, Kruskal-Wallis); median CRP: albumin ratio was 1.4, 1.8 and 0.6 (p=0.016). Median follow-up for AD, SD1 and SD2 groups was 1.6 (IQR 1.1-3.1), 4.9 (IQR 2.6-5.5) and 1.5 (IQR 0.9-2.3) years. Time to colectomy was shorter in SD1 (log rank p=0.0013); no significant difference in time to colectomy was observed comparing AD and SD2 groups (log rank p=0.32). 123 patients (84%) completed IFX induction and received maintenance therapy. Time to IFX discontinuation was shorter in SD1 (log rank p=0.009). CONCLUSION: Time to colectomy is significantly prolonged with use of AD IFX in selected ASUC patients with more severe disease. Historical use of standard IFX induction for all ASUC patients is associated with inferior long-term outcomes.

Irish data on the safety and efficacy of vedolizumab in the treatment of inflammatory bowel disease.

SUMMARY: This study reviews the safety and efficacy of treatment with vedolizumab for patients with inflammatory bowel disease across 9 Irish hospitals. It generates valuable and timely real-world data on treatment outcomes to add to the existing evidence base. Our population represents a refractory cohort with most patients previously exposed to at least one anti-TNFa agent and expressing an inflammatory phenotype. Results are reassuringly similar to larger international studies with additional insights into potential predictors of treatment response. This study further supports the safety and efficacy of vedolizumab in the treatment of inflammatory bowel disease. Key SummaryVedolizumab has growing real world data on its safety and efficacy in the treatment of IBD. Data on predictors of response are lacking. Studies such as VARSITY require new real-world data to help identify the place VDZ will occupy in the treatment algorithm for IBDThis study provides national Irish data on the safety and efficacy of VDZ in the treatment of IBD. It gives insight into various predictors of response for both UC and CD. It strengthens the available body of evidence on the use of VDZ and helps us determine its position on the treatment algorithm.

Pregnancy outcomes in inflammatory bowel disease patients treated with vedolizumab, anti-TNF or conventional therapy: results of the European CONCEIVE study.

BACKGROUND: Women with inflammatory bowel diseases (IBD) often receive biologicals during pregnancy to maintain disease remission. Data on outcome of vedolizumab-exposed pregnancies (VDZE) are sparse. AIMS: To assess pregnancy and child outcomes of VDZE pregnancies and to compare these results to anti-TNF exposed (TNFE) or both immunomodulatory and biologic unexposed (CON IBD) pregnancies. METHODS: A retrospective multicentre case-control observational study was performed. RESULTS: VDZE group included 79 pregnancies in 73 IBD women. The TNFE and CON IBD group included 186 pregnancies (162 live births) in 164 IBD women and 184 pregnancies (163 live births) in 155 IBD women, respectively. At conception, cases more often had active disease ([VDZE: 36% vs TNFE: 17%, P = .002] and [VDZE: 36% vs CON IBD: 24%, P = .063]). No significant difference in miscarriage rates were found between groups (VDZE and TNFE: 16% vs 13%, P = .567; VDZE and CON IBD: 16% vs 10%, P = .216). In live-born infants, median gestational age and birthweight were similar between groups. Median Apgar score at birth was numerically equal. Prematurity was similar in the VDZE group compared to the control groups, even when correcting for disease activity during pregnancy. The frequency of congenital anomalies was comparable between groups as were the percentages of breastfed babies. During the first year of life, no malignancies were reported and infants' infection risk did not significantly differ between groups. CONCLUSION: No new safety signal was detected in VDZE pregnancies although larger, prospective studies are required for confirmation.

DUBLIN [Degree of Ulcerative colitis Burden of Luminal Inflammation] Score, a Simple Method to Quantify Inflammatory Burden in Ulcerative Colitis.

BACKGROUND AND AIMS: Endoscopic scores of local severity do not reflect disease extent, or disease burden. The DUBLIN score is a simple bedside clinical score that estimates inflammatory burden using both disease severity and extent. As the need to personalize therapy for ulcerative colitis [UC] patients increases, a score accurately assessing disease burden will be of great relevance. The aim of this study was to assess the clinical utility of the DUBLIN score by comparing its performance with objective biomarkers. METHODS: The DUBLIN score was calculated as a product of the Mayo Endoscopic Score [0-3] and disease extent [E1-E3]. Correlation with objective biomarkers was performed in a retrospective 'discovery cohort'. A 'validation cohort was recruited from a single centre, where clinical outcomes, colectomy rate, and biochemical data were collected prospectively. RESULTS: The discovery cohort included 70 patients with UC. The DUBLIN score correlated significantly with faecal calprotectin [FCP] levels [r = 0.394; p < 0.01]. Receiver operating characteristic [ROC] analysis using FCP>50µg/g showed a higher area under the ROC curve [AUC] with the DUBLIN score [AUC = 0.76] than with the Mayo Score [AUC = 0.73]. The validation cohort included 41 patients. Patients with a high inflammatory burden [DUBLIN >3] had higher C-reactive protein and FCP, and lower albumin than patients with a low inflammatory burden. A high DUBLIN score was associated with an increased risk of treatment failure. [hazard ratio 2.98 95%, confidence interval 1.002-8.87; p = 0.049]. CONCLUSION: The DUBLIN score is a simple measure of inflammatory burden, which correlates with objective inflammatory markers and is associated with clinical outcomes, such as treatment failure. The DUBLIN score has the potential to assist in personalizing therapy for patients with UC.

Golimumab effectiveness and safety in clinical practice for moderately active ulcerative colitis.

BACKGROUND AND AIMS: Golimumab (GLB) is an antitumour necrosis factor-α (anti-TNF) therapy that has shown efficacy as induction and maintenance therapy for ulcerative colitis (UC). We aimed to describe the outcome of GLB therapy for UC in a real-world clinical practice. PATIENTS AND METHODS: Consecutive patients receiving GLB for UC in six Irish Academic Medical Centres were identified. The primary study endpoint was the 6-month corticosteroid-free remission rate. The secondary endpoints included the 3-month clinical response, time free of GLB discontinuation and adverse events. RESULTS: Seventy-two patients were identified [57% men; median (range) age of 41.4 years (20.3-76.8); disease duration 6.6 years (0-29.9); follow-up 8.7 months (0.4-39.2)]. Sixty-four percent of patients were anti-TNF naive. The 3-month clinical response and the 6-month corticosteroid-free remission rates were 55 and 39%, respectively. Forty-four percent of patients discontinued GLB during the follow-up, median (95% confidence interval) time to GLB discontinuation 18.7 months (9.2-28.1). A C-reactive protein more than 5 mg/l at baseline was associated with failure to achieve 6-month corticosteroid-free remission and a shorter time to GLB discontinuation, odds ratio 0.2 (0.1-0.7), P=0.008, and hazard ratio (95% confidence interval) 2.8 (1.3-5.7), P=0.007, respectively. Adverse events occurred in 7% of patients (n=5), all of which were minor and self-limiting. CONCLUSION: These real-world clinical data suggest that GLB is an effective and safe therapy for a UC cohort with significant previous anti-TNF exposure. An elevated baseline C-reactive protein, likely reflective of increased inflammatory burden, is associated with a reduced likelihood of a successful outcome of GLB therapy.

Protocol for a multicentred randomised controlled trial investigating the use of personalised golimumab dosing tailored to inflammatory load in ulcerative colitis: the GOAL-ARC study (GLM dose Optimisation to Adequate Levels to Achieve Response in Colitis) led by the INITIAtive group (NCT 0268772).

INTRODUCTION: Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD), often leading to an impaired quality of life in affected patients. Current treatment modalities include antitumour necrosis factor (anti-TNF) monoclonal antibodies (mABs) including infliximab, adalimumab and golimumab (GLM). Several recent retrospective and prospective studies have demonstrated that fixed dosing schedules of anti-TNF agents often fails to consistently achieve adequate circulating therapeutic drug levels (DL) with consequent risk of immunogenicity treatment failure and potential risk of hospitalisation and colectomy in patients with UC.The design of GLM dose Optimisation to Adequate Levels to Achieve Response in Colitis aims to address the impact of dose escalation of GLM immediately following induction and during the subsequent maintenance phase in response to suboptimal DL or persisting inflammatory burden as represented by raised faecal calprotectin (FCP). AIM: The primary aim of the study is to ascertain if monitoring of FCP and DL of GLM to guide dose optimisation (during maintenance) improves rates of patient continuous clinical response and reduces disease activity in UC. METHODS AND ANALYSIS: A randomised, multicentred two-arm trial studying the effect of dose optimisation of GLM based on FCP and DL versus treatment as per SMPC. Eligible patients will be randomised in a 1:1 ratio to 1 of 2 treatment groups and shall be treated over a period of 46 weeks. ETHICS AND DISSEMINATION: The study protocol was approved by the Research Ethics committee of St. Vincent's University Hospital. The results will be published in a peer-reviewed journal and shared with the worldwide medical community. TRIAL REGISTRATION NUMBERS: EudraCT number: 2015-004724-62; Clinicaltrials.gov Identifier: NCT0268772; Pre-results.

Ustekinumab Drug Levels in Maternal and Cord Blood in a Woman With Crohn's Disease Treated Until 33 Weeks of Gestation.

A 35-year old woman with ileocolonic, perianal, and vulval Crohn's disease was treated with subcutaneous ustekinuamb [USK] throughout pregnancy. Dose intervals were shortened from 6-weekly to 4-weekly to maintain clinical remission. The last dose of USK was administered at 33 weeks of gestation, and a healthy baby boy was delivered by caesarean section at 37 weeks. Maternal trough USK levels remained stable during pregnancy. Cord blood USK levels were nearly 2-fold higher than contemporaneous maternal serum levels. To our knowledge, this is the first report of maternal and cord USK levels in a patient with Crohn's disease.

CRP/Albumin Ratio: An Early Predictor of Steroid Responsiveness in Acute Severe Ulcerative Colitis.

INTRODUCTION: Identifying hospitalized patients with acute severe ulcerative colitis (ASUC) who will be refractory to corticosteroid therapy and require rescue therapy remains difficult. Hypoalbuminemia worsens with time during hospitalization and is associated with rapid clearance of and reduced response to infliximab (IFX) rescue. Early use of rescue therapy may therefore be more effective. Simple clinical and laboratory predictors of corticosteroid responsiveness would facilitate earlier use of rescue therapy. MATERIALS AND METHODS: Retrospective study of a prospectively maintained database of 3600 patients attending a single center was conducted. Patients with histologically confirmed ulcerative colitis admitted with ASUC over a 5-year period from January 2010 to December 2014 were identified. All patients initially received intravenous corticosteroids. Patient demographics were collected; C-reactive protein (CRP) and albumin levels were recorded at baseline and during admission. Receiver operating characteristic statistics were used to determine the optimal stool frequency, CRP, albumin, and CRP/albumin ratio (CAR) to predict steroid response. RESULTS: A total of 124 ASUC patients were admitted during a 5-year period. Median follow-up was 2.3 years. A total of 62 patients (50%) were steroid responsive, 55 patients (44%) received rescue IFX, 22 patients (18%) required colectomy within 30 days of admission, whereas a further 14 (11%) required colectomy during follow-up. By receiver operating characteristic statistics, day 3 CAR was a more accurate marker of steroid responsiveness than day 3 CRP or day 3 albumin alone [area under curve=0.75 (P<0.001)]. The optimal CAR to predict response to steroids on day 3 was 0.85 (sensitivity 70%, specificity 76%). When combined with D3 stool frequency, specificity improved to 83%. If at day 3, CAR was >0.85 and stool frequency was >3, the relative risk of steroid nonresponse was significantly raised at 3.9 (95% confidence interval, 2.1-7.2). CONCLUSIONS: Raised D3 CAR is an early predictor of steroid-refractory ASUC. When combined with D3 stool frequency, its predictive ability improves. In patients with predicted steroid nonresponse, early introduction of rescue IFX at this stage may be more effective, before serum albumin falls profoundly.

Determinants of short- and long-term survival from colorectal cancer in very elderly patients.

PURPOSE: Over 5100 colorectal cancers (CRCs) are diagnosed in the United Kingdom in 85 years and older age group per year but little is known of cancer progression in this group. We assessed clinical, pathological and molecular features of CRC with early and late mortality in such patients. METHODS: Data were analysed in relation to early mortality and long-term survival in 90 consecutive patients with CRC aged 85 years or older in a single hospital. RESULTS: Patients not undergoing operation, those with an ASA score of III or greater and those with advanced tumour stage were more likely to die within 30 days. Regression analysis showed that 30 day mortality was independently related to failure to undergo resection (odds ratio (O.R.), 10.0; 95% confidence interval [C.I.], 1.7-58.2; p=0.01) and an ASA score of III or greater (O.R. 13.0; 95% C.I., 1.4-12.6; p=0.03). All cause three and five year survival were 47% and 23% respectively for patients who are alive 30 days after diagnosis. Three and five year relative survivals were 64% and 54%, respectively. Long-term outcome was independently related to tumour stage (relative risk [R.R.], 2; 95% C.I., 1.3-3.1; p=0.001), presence of co-morbid diseases (R.R., 2.8; 95% C.I., 1.3-6.0; p=0.007) and lipid peroxidation status (R.R., 2.9; 95% C.I., 1.1-7.5; p=0.025). CONCLUSIONS: An active multidisciplinary approach to the care of patients with CRC at the upper extreme of life is reasonable. It also seems sensible to individualise care based upon the extent of disease at diagnosis and the presence of co-morbid conditions. Further studies to examine the role of lipid peroxidation are warranted.

Effects of radiation on levels of DNA damage in normal non-adjacent mucosa from colorectal cancer cases.

PURPOSE: Defects in DNA repair pathways have been linked with colorectal cancer (CRC). Adjuvant radiotherapy has become commonplace in the treatment of rectal cancer however it is associated with a higher rate of second cancer formation. It is known that radiation results in DNA damage directly or indirectly by radiation-induced bystander effect (RIBE) by causing double-strand breaks (DSBs). The majority of work in RIBE has been performed in cell lines and limited studies have been in or ex vivo. METHODS: The first study aim was to examine by immunohistochemistry, levels of DSB (expression of the protein MRE11) in normal colonic tissue outside the irradiated field post neo-adjuvant radiotherapy (group 1). These levels were compared to (a) irradiated tumour tissue post neo-adjuvant radiation within the same group, (b) a CRC patient group (group 2) who had not undergone neo-adjuvant radiotherapy and (c) a non-cancer patient group (group 3). The second aim was to determine if MRE11 expression levels were related to survival or radio-sensitivity post neo-adjuvant radiotherapy. RESULTS: There was a highly significant increase in MRE 11 expression in group 1 versus groups 2 and 3 (p < 0.001). There was no association between MRE11 levels and survival or radio-sensitivity. CONCLUSION: Our findings show radiotherapy causes DSBs at significantly higher levels in normal colonic mucosa of patients post neo-adjuvant treatment which may represent RIBE. If this damage remains unrepaired, increased levels of genomic instability may contribute to the higher occurrence of second cancers in patients treated post neo-adjuvant radiotherapy.

The effect of green tea on oxidative damage and tumour formation in Lobund-Wistar rats.

A number of epidemiological studies suggest that the consumption of green tea reduces the incidence of prostate cancer. As the major catechins present in green tea are potent antioxidants, we hypothesized that genetic and cellular damage induced by oxygen free radicals could be significantly reduced by potent antioxidants in green tea, thus reducing the cumulative genetic and cellular damage with age, and slowing or preventing tumour formation. Long-term administration of a decaffeinated green tea extract to Lobund-Wistar rats for periods up to 26 months almost halved the incidence of primary tumours in the genitourinary tract when compared with an age-matched cohort receiving just water. We observed no inhibition of DNA adduct formation or lipid peroxidation in animals consuming green tea compared with animals consuming deionized water. The decrease in tumour formation was associated with an increase in 8-hydroxy-2'deoxyguanosine and 4-hydroxynonenal content (markers of DNA adduct formation and lipid peroxidation, respectively) in the epithelium of the ventral prostate in aging animals. In addition, there was an increase in 8-hydroxy-2'deoxyguanosine expression, but no change in 4-hydroxynonenal expression in the seminal vesicles of older animals. An age-associated increase in expression of the antioxidant enzymes manganese superoxide dismutase and catalase in the epithelium of the ventral prostate of aging animals was observed. Furthermore, there was also an increase in manganese superoxide dismutase expression, but no change in catalase expression in the seminal vesicles of older animals. These data demonstrate that consumption of green tea decreases the incidence of genitourinary tract tumours in the Lobund-Wistar rat, but has no effect on age-associated DNA adduct formation and lipid peroxidation in the ventral prostate and seminal vesicles of the aging rat.