Eastern Canadian Colorectal Cancer Consensus Conference 2017

The annual Eastern Canadian Gastrointestinal Cancer Consensus Conference 2017 was held in St. John's, Newfoundland and Labrador, 28-30 September. Experts in radiation oncology, medical oncology, surgical oncology, and cancer genetics who are involved in the management of patients with gastrointestinal malignancies participated in presentations and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses multiple topics in the management of gastric, rectal, and colon cancer, including ■ identification and management of hereditary gastric and colorectal cancer (crc);■ palliative systemic therapy for metastatic gastric cancer;■ optimum duration of preoperative radiation in rectal cancer-that is, short- compared with long-course radiation;■ management options for peritoneal carcinomatosis in crc;■ implications of tumour location for treatment and prognosis in crc; and■ new molecular markers in crc.

Gastrointestinal stromal tumours: etiology, pathology and clinical management

Investigation of the regulation of cell growth, differentiation and death by signalling pathways has led to a greater understanding of how alterations in these pathways play a critical role in the development of some cancers, and has opened new opportunities for their treatment. In the present review, results with the prototype drug of this class, imatinib (Gleevec, Glivec [formerly STI571]; Novartis, Switzerland), in metastatic gastrointestinal stromal tumours are presented. The present review originated from a conference of the authors held in Montreal, Quebec in June 2003, under the sponsorship of Novartis.

Phase I clinical trial of the anti-EGFR monoclonal antibody nimotuzumab with concurrent external thoracic radiotherapy in Canadian patients diagnosed with stage IIb, III or IV non-small cell lung cancer unsuitable for radical therapy

PURPOSE

Many patients with non-small cell lung cancer (NSCLC) are eligible only for palliative radiation (RT) at presentation. This study was designed to assess the feasibility of adding the anti-EGFR monoclonal antibody nimotuzumab to palliative thoracic RT.

METHODS

Patients with stage IIB, III or IV NSCLC considered unsuitable for radical radiation or chemo-radiation received nimotuzumab weekly 8× (100, 200 or 400 mg) with radiation (30 or 36 Gy in 3 Gy fractions). If response or disease stability was observed, nimotuzumab was continued every other week starting from week 10 until progression or toxicity.

RESULTS

Eighteen patients were enrolled: 6 at 100 mg, 7 at 200 mg, 5 at 400 mg nimotuzumab. Patient characteristics included median age 69 years, 11 males, 17 smokers, 17 Caucasians, stage IIIA/IIIB/IV 2/7/9, 5 Eastern Cooperative Oncology Group performance status (PS) 2; 9 adenocarcinoma. The most commonly reported adverse events were fatigue, anorexia, chills, pain and hypophosphatemia (grades 1 to 2 in most patients). No severe skin or allergic toxicity was noted. No dose-limiting toxicity was encountered. Objective response rate and disease control rate inside the radiation field were 66 and 94.0%, respectively.

CONCLUSION

Nimotuzumab administered concurrently with palliative thoracic radiation is well tolerated at each of the three doses investigated in NSCLC patients unsuitable for radical treatment. The low toxicity and absence of rash make this combination therapeutically attractive for frail patients with other co-morbidities and poor performance status. These results support further testing of this regimen in the phase II setting.

Genetic association studies of interleukin-13 receptor alpha1 subunit gene polymorphisms in asthma and atopy

Interleukin (IL)-13 plays a central role in asthma pathogenesis by binding to the IL-13 receptor, which is a heterodimer composed of the IL-13 receptor alpha1 subunit (IL-13Ralpha1) and IL-4Ralpha. The genetic diversity at the IL-13Ralpha1 gene (IL13RA1) locus on chromosome Xq24 was characterised and the association of identified polymorphisms with asthma and atopy phenotypes examined. The promoter and coding region of IL13RA1 were screened for common genetic variants, and polymorphisms found were genotyped in a large cohort of 341 asthmatic Caucasian families (each containing at least two asthmatic siblings) and 182 nonasthmatic control subjects. Genetic association was determined using case-control and transmission disequilibrium test analyses. Two common polymorphisms were identified, a newly found thymidine (T) to guanine (G) transition of nucleotide -281 (-281T>G) single nucleotide polymorphism in the IL13RA1 promoter and the previously described 1365A>G variant in the IL13RA1 proximal 3' untranslated region. No significant association of either -281T>G or 1365A>G with risk of asthma or atopy phenotypes was found, apart from a suggestive association between the IL13RA1 -281T/1365A haplotype and raised total serum immunoglobulin E levels in adult female asthmatics. These findings indicate that the interleukin-13 receptor alpha1 subunit gene -281T>G and 1365A>G polymorphisms do not contribute to asthma susceptibility or severity, although the interleukin-13 receptor alpha1 subunit gene locus might be involved in the control of immunoglobulin E production.

Polymorphism of the mast cell chymase gene (CMA1) promoter region: lack of association with asthma but association with serum total immunoglobulin E levels in adult atopic dermatitis

BACKGROUND

Mast cell chymase has the potential to be an important mediator of inflammation and remodelling in the asthmatic lung. Previous studies have examined association between promoter polymorphism of the chymase gene (CMA1) and allergic phenotypes but the significance of this polymorphism is unclear. We have examined association of a CMA1 variant in relation to asthma in a large UK Caucasian family cohort.

METHODS

A polymorphism of the CMA1 gene promoter (-1903G/A) was genotyped in 341 asthmatic families and in 184 non-asthmatic adults recruited from the UK PCR-RFLP based genotyping. Association with asthma diagnosis, atopy, specific and total IgE, and atopy and asthma severity was examined.

RESULTS

Case-control studies did not reveal a significant difference in allele frequency between asthmatics and controls. A significant association was found between CMA1 genotypes and total IgE levels in subjects with self-reported eczema that remained significant after correction for multiple testing (median total serum IgE GG 297 kU/L, GA 144 kU/L, AA 48.4 kU/L, Pc=0.0032).

CONCLUSION

These data suggest that CMA1 promoter polymorphism does not contribute to asthma susceptibility or severity but may be involved in regulating IgE levels in patients with eczema.

Toll-like receptor 4 polymorphism and severity of atopy in asthmatics

Endotoxin exposure may have a protective effect against asthma and atopy. An Asp299Gly polymorphism in the Toll-like receptor 4 (TLR4) gene reduces responsiveness to endotoxin. This study determined the effect of TLR4 polymorphism on the risk and severity of asthma and atopy. In all, 336 UK Caucasian families with > or = 2 affected sibs (physician's diagnosis of asthma and current medication use) and 179 Caucasians without asthma or a family history of asthma were genotyped using ARMS-PCR. No association of the TLR4 polymorphism was found with the risk of developing asthma, either in parent-affected sibling trios, or in case-control analyses (P>0.05). In the first affected asthmatic siblings, the atopy severity score (based on size and number of positive skin-prick tests and specific IgE) was higher in those with the Asp/Gly or Gly/Gly genotypes (mean 1.8, s.d. 1.1, n=39) compared to those with the Asp/Asp genotype (mean 1.2, s.d. 1.0, n=279) (P=0.003, t-test). No associations were found with total IgE, FEV(1) % predicted, slope of FEV(1) response to methacholine or asthma severity score (P>0.05). This study confirms the previously observed lack of association of TLR4 polymorphisms with asthma. In contrast, the findings suggest that genetically determined hyporesponsiveness to endotoxin may increase atopy severity.

Promoter polymorphism in the 5-lipoxygenase (ALOX5) and 5-lipoxygenase-activating protein (ALOX5AP) genes and asthma susceptibility in a Caucasian population

BACKGROUND

5-Lipoxygenase (5-LO) and 5-lipoxygenase-activating protein (FLAP) are essential for cysteinyl-leukotriene (cys-LT) production, critical mediators in asthma.

OBJECTIVE

We sought to identify novel promoter polymorphisms within the FLAP (ALOX5AP) gene promoter and test the role of these and the previously identified 5-LO (ALOX5) Sp1 promoter polymorphism in asthma susceptibility.

METHODS

To assess genetic association with asthma phenotypes, we genotyped 341 Caucasian families (containing two asthmatic siblings) and non-asthmatic control subjects (n=184). Genetic association was determined by case-control and transmission disequilibrium test (TDT) analyses. To determine the functional role of polymorphisms on basal transcription, we generated ALOX5AP-promoter-luciferase constructs and transiently transfected human HeLa cells.

RESULTS

A novel G/A substitution at -336 bp and a poly(A) repeat (n=19 or 23) at position -169 to -146 bp were identified in the ALOX5AP promoter. Genotyping found the -336 A and poly(A19) alleles at frequencies of q=0.06 and 0.12, respectively. No ALOX5AP allele was associated with asthma or asthma-related phenotypes in case-control or TDT analyses. ALOX5AP-promoter-luciferase analyses did not support a functional role of the -336 or poly(A) polymorphism in determining basal transcription. The ALOX5 Sp1 polymorphism was predominantly homozygous wild-type 5/5 (frequency q=0.70) and heterozygous 4/5 (q=0.23) genotypes and no allele was associated with asthma or asthma-related phenotypes.

CONCLUSION

Taken together, these data do not support a significant role for these polymorphisms in genetic susceptibility to asthma in the Caucasian population.

Polymorphisms in the interleukin-4 and interleukin-4 receptor alpha chain genes confer susceptibility to asthma and atopy in a Caucasian population

BACKGROUND

IL-4 by binding to its receptor (IL-4R) is essential for the development of airway inflammation present in asthma, through the induction of IgE synthesis in B cells and differentiation of T cells to a Th2 phenotype.

OBJECTIVE

To investigate the role of four common polymorphisms in the IL-4 (IL4-34CT and IL4-589CT) and IL-4Ralpha chain (IL4RAI50V and IL4RAQ576R) genes in conferring susceptibility to the development of atopy and/or asthma.

METHODS

Two polymorphisms in the IL-4 gene promoter, IL4-34CT and IL4-589CT, and two polymorphisms in the IL-4Ralpha chain gene, IL4RAI50V and IL4RAQ576R, have been genotyped using PCR-based methods in 341 asthmatic families and in 184 non-asthmatic adults recruited from the south of England.

RESULTS

Case-control analysis did not reveal differences in the distribution of the four polymorphisms between asthmatics and controls. However, the transmission disequilibrium test showed that the IL4-589 T allele was preferentially transmitted to asthmatic children (P=0.036) and that the IL4RAQ576 was preferentially transmitted to children with atopic asthma (P=0.018). Haplotype analysis showed a strong association between the IL4-34T/-589T haplotype and asthma per se (P=0.041), and a strong association between the IL4RA I50/Q576 haplotype and atopic asthma (P=0.006).

CONCLUSION

Our data suggest that polymorphisms in the IL-4 and IL-4Ralpha chain genes might play a role both conferring susceptibility to and modulating severity of atopy and asthma.

Allelic association and functional studies of promoter polymorphism in the leukotriene C4 synthase gene (LTC4S) in asthma

BACKGROUND

LTC4 synthase is essential for the production of cysteinyl leukotrienes (Cys-LT), critical mediators in asthma. We have identified a novel promoter polymorphism at position -1072 (G/A) and a -444 (A/C) polymorphism has previously been reported. The role of these polymorphisms in the genetic susceptibility to asthma was examined.

METHODS

To test for genetic association with asthma phenotypes, 341 white families (two asthmatic siblings) and 184 non-asthmatic control subjects were genotyped. Genetic association was assessed using case control and transmission disequilibrium test (TDT) analyses. LTC4S promoter luciferase constructs and transiently transfected human HeLa and KU812F cells were generated to determine the functional role of these polymorphisms on basal transcription.

RESULTS

No associations were observed in case control analyses (-1072 A, q=0.09; -444 C, q=0.29); the TDT identified a borderline association between the -444 C allele and bronchial responsiveness to methacholine (p=0.065). Asthmatic children with the -444 C allele had a lower mean basal forced expiratory volume in 1 second (97.4 v 92.7% predicted, p=0.005). LTC4S promoter luciferase analyses provided no evidence for a functional role of either polymorphism in determining basal transcription.

CONCLUSION

This study does not support a role for these polymorphisms in genetic susceptibility to asthma but provides evidence to suggest a role in determining lung function parameters.

Evolving concepts on the value of adenosine hyperresponsiveness in asthma and chronic obstructive pulmonary disease

Adenosine is a purine nucleoside which mediates a variety of cellular responses relevant to asthma and COPD through interaction with specific receptors. Administration of adenosine by inhalation to patients with asthma and COPD is known to cause concentration related bronchoconstriction. Responses elicited by this purine derivative in asthma and COPD should not be considered as a mere reflection of non-specific airways hyperresponsiveness. Evaluation of airways responsiveness by adenosine induced bronchoconstriction may be valuable in differentiating asthma from COPD, monitoring of anti-inflammatory treatment in asthma, surveying disease progression, and assessing disease activity in relation to allergic airways inflammation.

Role of cysteinyl leukotrienes in adenosine 5'-monophosphate induced bronchoconstriction in asthma

BACKGROUND

Adenosine induced bronchoconstriction in patients with asthma is thought to be mediated by the synthesis and release of autacoids from airway mast cells. In vitro, adenosine induced constriction of asthmatic bronchi is blocked by a combination of specific histamine and cysteinyl leukotriene receptor antagonists, but the relative contribution of these mediators in vivo is unclear. We hypothesised that adenosine induced bronchoconstriction in asthmatic patients may be blocked by pretreatment with the orally active selective cysteinyl leukotriene-1 (CysLT(1)) receptor antagonist, montelukast.

METHODS

In a randomised, double blind, crossover study, oral montelukast (10 mg) or placebo was administered once daily on two consecutive days to 18 patients with mild to moderate persistent atopic asthma. Incremental doses of adenosine 5'-monophosphate (AMP) from 0.39 to 400 mg/ml were inhaled by dosimeter and the dose producing a 20% fall in FEV(1) (PC(20)AMP) after AMP inhalation was recorded. Leukotriene E(4) (LTE(4)) urinary concentrations were measured by enzyme immunoassay 4 hours after AMP challenge.

RESULTS

Montelukast pretreatment provided highly significant protection against adenosine induced bronchoconstriction, with geometric mean PC(20)AMP values of 52.6 mg/ml (95% CI 35.2 to 78.7) after placebo and 123.9 mg/ml (95% CI 83.0 to 185.0) after montelukast (p=0.006). The geometric mean of the montelukast/placebo PC(20)AMP ratio was 2.4 (95% CI 1.3 to 4.2). Montelukast had no significant effect on 4 hour urinary excretion of LTE(4) compared with placebo.

CONCLUSIONS

Selective CysLT(1) receptor antagonism with montelukast provides highly significant protection against AMP induced bronchoconstriction in patients with atopic asthma, implying that cysteinyl leukotrienes are generated from airway mast cells through preferential activation of their A(2B) receptors.

Prognostic significance of BAG-1 expression in nonsmall cell lung cancer

The purpose of this study was to evaluate the expression of BAG-1 in a cohort of patients with nonsmall cell lung cancer (NSCLC). The intensity and subcellular distribution of BAG-1 expression were correlated with overall survival. Tumor samples were collected from 85 patients diagnosed with NSCLC between 1993-1995 in St. John's, Newfoundland. Expression of BAG-1 was determined by immunohistochemistry using polyclonal anti-BAG-1 antibody. There was significant variation in the immunohistochemical staining patterns of BAG-1, including nonstaining and staining of either the cytoplasm, nucleus or both. Univariate Cox regression analysis showed that those patients whose tumor overexpressed BAG-1 had a significant reduction in the risk of death (hazard ratio = 0.53, p = 0.03). The survival advantage of patients with BAG-1 overexpression tumor was also demonstrated by Kaplan-Meier analysis and log-rank tests (median survival 30.10 months versus 17.04 months, p = 0.05). In addition, multivariate Cox regression analysis showed that patients whose tumor exhibited intense cytoplasmic staining had a further reduction of the risk of death (hazard ratio = 0.42, p = 0.03) and this effect was independent of age, stage and histology. All stages were included in the analysis. Our preliminary data strongly indicate that further investigation is warranted to better define the role of BAG-1 as an independent prognostic factor in NSCLC.

Prognostic significance of BAG-1 expression in nonsmall cell lung cancer

The purpose of this study was to evaluate the expression of BAG-1 in a cohort of patients with nonsmall cell lung cancer (NSCLC). The intensity and subcellular distribution of BAG-1 expression were correlated with overall survival. Tumor samples were collected from 85 patients diagnosed with NSCLC between 1993-1995 in St. John's, Newfoundland. Expression of BAG-1 was determined by immunohistochemistry using polyclonal anti-BAG-1 antibody. There was significant variation in the immunohistochemical staining patterns of BAG-1, including nonstaining and staining of either the cytoplasm, nucleus or both. Univariate Cox regression analysis showed that those patients whose tumor overexpressed BAG-1 had a significant reduction in the risk of death (hazard ratio = 0.53, p = 0.03). The survival advantage of patients with BAG-1 overexpression tumor was also demonstrated by Kaplan-Meier analysis and log-rank tests (median survival 30.10 months versus 17.04 months, p = 0.05). In addition, multivariate Cox regression analysis showed that patients whose tumor exhibited intense cytoplasmic staining had a further reduction of the risk of death (hazard ratio = 0.42, p = 0.03) and this effect was independent of age, stage and histology. All stages were included in the analysis. Our preliminary data strongly indicate that further investigation is warranted to better define the role of BAG-1 as an independent prognostic factor in NSCLC.