Kevin Zbuk

Declining incidence of breast cancer after decreased use of hormone-replacement therapy: magnitude and time lags in different countries

Throughout the latter half of the 20th century, hormone-replacement therapy (HRT) use steadily increased in the Western world. In 2002, the early termination of the Womens Health Initiative trial due to an excess of adverse events attributable to HRT, led to a precipitous decline in its use. Breast cancer incidence began to decline soon thereafter in the USA and several other countries. However, the magnitude of the decline in breast cancer incidence, and its timing with respect to HRT cessation, shows considerable variability between nations. The impact of HRT cessation appears most significant and immediate in countries with the largest absolute decline in HRT use. In countries in which peak prevalence of HRT use was high, several studies have convincingly excluded decreasing rates of mammographic screening as an explanation for the decline in breast cancer incidence. Conversely, in some countries, no decline in breast cancer incidence is apparent that can be readily attributed to declining trends in HRT use. In such cases, declines in breast cancer incidence may be related instead to saturation or decreased utilisation of mammographic screening programmes. In other cases, it is difficult to disentangle the respective influence of trends in HRT use, and the influence of changes relating to mammographic screening. However, irrespective of time lags and varying magnitudes of effect, the data convincingly support a direct association between decreasing HRT use and declining breast cancer incidence.

Epidermal growth factor receptor: pathway, therapies, and pipeline.

BACKGROUND The epidermal growth factor receptor (EGFR) pathway is important in tumor growth, survival, and metastasis and is now the target of several therapeutic agents. OBJECTIVES This paper seeks to review the EGFR pathway, the study and use of EGFR-directed agents in non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC), and related new drug development. METHODS PubMed was searched for English-language articles by MeSH and title terms of EGFR published from 2006 to 2013, using the limits of clinical trials as well as reviews. Reference lists were assessed for relevant articles, and guidelines were searched. Clinicaltrials.gov and meeting abstracts were queried for investigational agents. Eligible papers included those concerning EGFR biology, NSCLC or CRC studies involving EGFR-directed agents, and/or investigational drugs targeting EGFR and/or associated pathways. RESULTS The activity of oral tyrosine kinase inhibitors (TKIs) against EGFR has improved survival in NSCLC, and these agents particularly effective in cancers with an EGFR mutation. Resistance to TKIs is most commonly related to a second, T790M, mutation, or to MET amplification, with newer agents directed against these mechanisms. Conversely, in CRC, TKIs have been ineffective, whereas monoclonal antibodies have improved survival. Both primary and secondary KRAS mutations in CRC abrogate mAb effectiveness. Several targets, including MET, BRAF, and PI3K, may serve useful in combination with anti-EGFR drugs. CONCLUSIONS Exploitation of EGFR-directed therapies has offered improvement in survival and quality of life in NSCLC and CRC. New therapies directed at EGFR may offer further improvements. However, resistance mechanisms suggest that combination therapies or multitargeted agents will be crucial in making significant future advances.

Accelerated muscle and adipose tissue loss may predict survival in pancreatic cancer patients: the relationship with diabetes and anaemia.

Weight loss leading to cachexia is associated with poor treatment response and reduced survival in pancreatic cancer patients. We aim to identify indicators that allow for early detection that will advance our understanding of cachexia and will support targeted anti-cachexia therapies. A total of fifty pancreatic cancer patients were analysed for skeletal muscle and visceral adipose tissue (VAT) changes using computed tomography (CT) scans. These changes were related to physical characteristics, secondary disease states and treatment parameters. Overall, patients lost 1.72 (SD 3.29) kg of muscle and 1.04 (SD 1.08) kg of VAT during the disease trajectory (413 (SD 213) d). After sorting patients into tertiles by rate of VAT and muscle loss, patients losing VAT at > -0.40 kg/100 d had poorer survival outcomes compared with patients with < -0.10 kg/100 d of VAT loss (P= 0.020). Patients presenting with diabetes at diagnosis demonstrated significantly more and accelerated VAT loss compared with non-diabetic patients. In contrast, patients who were anaemic at the first CT scan lost significantly more muscle tissue and at accelerated rates compared with non-anaemic patients. Accelerated rates of VAT loss are associated with reduced survival. Identifying associated features of cachexia, such as diabetes and anaemia, is essential for the early detection of cachexia and may facilitate the attenuation of complications associated with cachexia.

Colorectal Cancer in Young Adults

Colorectal cancer (CRC) is rare in young adults. It presents more frequently with stage 3 or 4 disease, underscoring its relevance in this population. Prognosis, matched for stage of disease at presentation, is likely similar to that in older adults, although survival is clearly lower for the youngest subgroups within this population. This article reviews the literature on the etiology, presentation, treatment, and outcome of CRC in young adults. New chemotherapeutic regimens have demonstrated survival benefits and the introduction of new biological agents has offered ways to control metastatic disease that may eventually show promise in the treatment of earlier-stage CRC. The benefit of these newer agents in young adults is assumed but currently unproven. Molecular genetic studies are increasing the understanding of the pathobiology of CRC and may ultimately allow at-risk patients to be identified at an earlier stage.

BRCA2 variants and cardiovascular disease in a multi-ethnic study.

BackgroundGermline mutations of BRCA1/2 are associated with hereditary breast and ovarian cancer. Recent data suggests excess mortality in mutation carriers beyond that conferred by neoplasia, and recent in vivo and in vitro studies suggest a modulatory role for BRCA proteins in endothelial and cardiomyocyte function. We therefore tested the association of BRCA2 variants with clinical cardiovascular disease (CVD).MethodsUsing data from 1,170 individuals included in two multi-ethnic population-based studies (SHARE and SHARE-AP), the association between BRCA2 variants and CVD was evaluated. 15 SNPs in BRCA2 with minor allele frequencies (MAF) > 0.01 had been previously genotyped using the cardiovascular gene-centric 50 k SNP array. 115 individuals (9.8%) reported a CVD event, defined as myocardial infarction (MI), angina, silent MI, stroke, and angioplasty or coronary artery bypass surgery. Analyses were adjusted for age and sex. The SNPs rs11571836 and rs1799943 were subsequently genotyped using the MassARRAY platform in 1,045 cases of incident MI and 1,135 controls from the South Asian subset of an international case-control study of acute MI (INTERHEART), and rs11571836 was imputed in 4,686 cases and 4500 controls from the Pakistan Risk of Myocardial Infarction Study (PROMIS).ResultsTwo BRCA2 SNPs, rs11571836 and rs1799943, both located in untranslated regions, were associated with lower risk of CVD (OR 0.47 p = 0.01 and OR 0.56 p = 0.03 respectively) in the SHARE studies. Analysis by specific ethnicities demonstrated an association with CVD for both SNPs in Aboriginal People, and for rs11571836 only in South Asians. No association was observed in the European and Chinese subgroups. A non-significant trend towards an association between rs11571836 and lower risk of MI was observed in South Asians from INTERHEART [OR = 0.87 (95% CI: 0.75-1.01) p = 0.068], but was not evident in PROMIS [OR = 0.96 (95% CI: 0.90-1.03) p = 0.230]. Meta-analysis of both case-control studies resulted in a combined OR of 0.94 (95% CI: 0.89-1.004, p = 0.06).ConclusionsAlthough there was an association between two SNPs in BRCA2 and CVD in a multi-ethnic population, these results were not replicated in two South Asian case-control studies of incident MI. Future studies exploring the association between BRCA variants and cardiovascular disorders are needed to clarify the role, if any, for BRCA variants in CVD pathogenesis.

Targeted metabolomics in colorectal cancer: a strategic approach using standardized laboratory tests of the blood and urine

Background Glycolytic markers have been detected in colorectal cancer (CRC) using advanced analytical methods. Methods Using commercially available assays, by-products of anaerobic metabolism were prospectively measured in the blood and urine of 20 patients with metastatic colorectal cancer (mCRC) and 20 patients with local disease. Twenty-four-hour urine citrate, plasma lactate, ketones, venous blood gas, anion gap, and osmolar gap were investigated. Results of patients with metastatic and local CRC were compared using two-sample t-tests or equivalent nonparametric tests. In addition, plasma total CO2 concentrations in our local hospital (5,931 inpatients and 1,783 outpatients) were compared retrospectively with those in our dedicated cancer center (1,825 outpatients) over 1 year. Results The average venous pCO2 was higher in patients with mCRC (50.2 mmHg; standard deviation [SD]=9.36) compared with those with local disease (42.8 mmHg; SD=8.98), p=0.045. Calculated serum osmolarity was higher in mCRC and attributed to concomitant sodium and urea elevations. In our retrospective analysis, plasma total CO2 concentrations (median=27 mmol/L) were higher in cancer patients compared to both hospital inpatients (median=23 mmol/L) and outpatients (median=24 mmol/L), p<0.0001. Conclusion Patients with mCRC had higher venous pCO2 levels than those with local disease. Although causation cannot be established, we hypothesize that pCO2 elevation may stem from a perturbed metabolism in mCRC.

Quality of preoperative pelvic computed tomography (CT) and magnetic resonance imaging (MRI) for rectal cancer in a region in Ontario: A retrospective population-based study

Treatment decisions for rectal cancer rely on preoperative staging with CT and MRI scans. We assessed the quality of such scans in a region of Ontario.

Utility of the Edmonton Frail Scale in identifying frail elderly patients during treatment of colorectal cancer

BACKGROUND Frailty has been proposed by geriatricians as an indicator of functional age. The Edmonton Frail Scale (EFS) is a 15-point incremental scale; it is quick (<5 min), and simple to administer. We conducted an exploratory study to establish if the EFS add utility to clinicians expertise by determining if there was an association between EFS and receipt of chemotherapy in colorectal cancer (CRC) patients. METHODS The EFS was administered to stage II-IV CRC patients ≥70 years. EFS assessment was completed by one of the investigators, with the treating oncology team blinded to the results. RESULTS A total of 46 patients were enrolled, and the EFS was reproduced in 32 patients at two visits (r=0.81; 95% CI: 0.64-0.90, P<0.0001). There was no correlation between the EFS and receipt of chemotherapy for the study population as a whole; however, exclusion of stage II patients showed a reduced likelihood of receiving chemotherapy with higher EFS scores (odds ratio 0.56; 95% CI: 0.37-0.85, P<0.01 per unit increment). A similar effect was observed after multivariable analysis (adjusting for performance status, age, stage and gender, odds ratio 0.41 95% CI: 0.18-0.96, P<0.05 per unit increment). CONCLUSIONS This exploratory study suggests that EFS can identify patients that oncologists may have thought were too frail for chemotherapy, independent of PS. Therefore, the EFS has the potential to add a reproducible, and quantifiable measure of frailty to the clinicians decision making toolset. A follow up study will employ the EFS in real-time, and determine if using the EFS can minimize complications and unplanned health care utilization in elderly cancer patients.

Association between the Lynch syndrome gene MSH2 and breast cancer susceptibility in a Canadian familial cancer registry

Background Previous studies assessing breast cancer risk in families with Lynch syndrome (LS) have yielded conflicting results. Furthermore, conclusions are limited by small sample size and few breast cancer outcomes. This study assesses breast cancer risk in a large prospectively followed LS cohort. Methods Pedigrees of 325 unrelated families with LS within the Familial Gastrointestinal Cancer Registry in Canada were examined for breast cancer diagnoses. Standardised incidence ratios (SIR) and lifetime cumulative incidence calculations were used to compare the incidence of breast cancer in mutation carriers with the general population. Results Forty-one mutation carriers diagnosed with breast cancer belonging to 34 unrelated families were identified. Mean age at diagnosis was 54 years. The mutation distribution among the LS patients with breast cancer was statistically different from those without breast cancer (p=0.015), reflecting the predominance of MSH2 mutations among affected patients (74%). Eighty-eight per cent of LS families with breast cancer met Amsterdam criteria, compared with 49% of LS families without breast cancer (p=0.03). Lifetime cumulative incidence of breast cancer in female MSH2 mutation carriers in our cohort was 22% (p<0.001). The SIR for breast cancer of female MSH2 mutation carriers in our cohort was 3.11 (95% CI 1.95 to 4.71). Conclusions An increased risk of breast cancer in MSH2 mutation carriers was demonstrated in a Canadian familial cancer registry. Women with breast cancer often had a personal and family history of multiple LS-related malignancies. These results suggest a potential role for intensified breast cancer surveillance among women with LS.

Classification of a VUS in MLH1 using a combination of family segregation studies and protein biochemistry.

342 Background: The identification of variants of unknown clinical significance (VUS) presents a challenge for diagnostic laboratories and clinicians working with families with Lynch syndrome (LS). Although a variety of strategies exist to attempt clarification, data from multiple sources is often required before a VUS is re-classified to pathogenic or benign. Methods: We report on the investigation of 2 families with a variant in the MMR gene MLH1, c.2038T>C (p.Cys680Arg). In addition to segregation analysis, and review of published literature, the c-terminal domain of MLH1was cloned, the p.Cys680Arg variant was generated using site-directed mutagenesis and protein expression was induced. In addition, this point mutation was modelled onto the crystal structure of the dimerization domain of MLH1. Results: Both families fit Amsterdam criteria for a diagnosis of LS. All available tumours exhibited MLH1 deficiency and microsatellite instability and all living affected individuals available were positive for ...