| 31. |
- Myte, Robin, et al.
(författare)
-
Components of One-carbon Metabolism Other than Folate and Colorectal Cancer Risk
- 2016
-
Ingår i: Epidemiology. - 1044-3983 .- 1531-5487. ; 27:6, s. 787-796
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Despite extensive study, the role of folate in colorectal cancer remains unclear. Research has therefore begun to address the role of other elements of the folate-methionine metabolic cycles. This study investigated factors other than folate involved in one-carbon metabolism, i.e., choline, betaine, dimethylglycine, sarcosine, and methionine and relevant polymorphisms, in relation to the risk of colorectal cancer in a population with low intakes and circulating levels of folate.METHODS: This was a prospective case-control study of 613 case subjects and 1,190 matched control subjects nested within the population-based Northern Sweden Health and Disease Study. We estimated odds ratios (OR) by conditional logistic regression, and marginal risk differences with weighted maximum likelihood estimation using incidence data from the study cohort.RESULTS: Higher plasma concentrations of methionine and betaine were associated with modest colorectal cancer risk reductions (OR [95% confidence interval {CI}] for highest versus lowest tertile: 0.76 [0.57, 0.99] and 0.72 [0.55, 0.94], respectively). Estimated marginal risk differences corresponded to approximately 200 fewer colorectal cancer cases per 100,000 individuals on average. We observed no clear associations between choline, dimethylglycine, or sarcosine and colorectal cancer risk. The inverse association of methionine was modified by plasma folate concentrations (OR [95% CI] for highest/lowest versus lowest/lowest tertile of plasma methionine/folate concentrations 0.39 [0.24, 0.64], Pinteraction = 0.06).CONCLUSIONS: In this population-based, nested case-control study with a long follow-up time from baseline to diagnosis (median: 8.2 years), higher plasma concentrations of methionine and betaine were associated with lower colorectal cancer risk. See Video Abstract at http://links.lww.com/EDE/B83.
|
|
| 32. |
- Myte, Robin, et al.
(författare)
-
Metabolic factors and the risk of colorectal cancer by KRAS and BRAF mutation status
- 2019
-
Ingår i: International Journal of Cancer. - : John Wiley & Sons. - 0020-7136 .- 1097-0215. ; 145:2, s. 327-337
-
Tidskriftsartikel (refereegranskat)abstract
- Factors related to energy metabolism and the metabolic syndrome, such as higher body mass index (BMI), blood glucose, or blood lipids, and blood pressure, are associated with an increased risk of colorectal cancer (CRC). However, CRC is a heterogeneous disease, developing through distinct pathways with differences in molecular characteristics and prognosis, and possibly also in risk factors. For subtypes defined by KRAS and BRAF mutation status, BMI is the only metabolic factor previously studied, with inconsistent findings. We investigated whether associations between BMI, blood glucose, blood lipids, and blood pressure and CRC risk differed by tumor KRAS and BRAF mutation status in 117,687 participants from two population-based cohorts within the Northern Sweden Health and Disease Study (NSHDS). Hazard ratios (HRs) for overall CRC and CRC subtypes by metabolic factors were estimated with Cox proportional hazards regression, using multiple imputation to handle missing exposure and tumor data. During a median follow-up of 15.6 years, we acquired 1,250 prospective CRC cases, of which 766 cases had complete baseline and molecular tumor data. Consistent with previous evidence, higher BMI, total cholesterol, triglyceride levels, and blood pressure were associated with an increased risk of overall CRC (HRs per 1 standard deviation increase: 1.07 to 1.12). These associations were similar regardless of CRC subtype by KRAS and BRAF mutation status (all pheterogeneity > 0.05). The same was true for subtypes based on microsatellite instability status. Poor metabolic health may therefore be a universal mechanism for colorectal cancer, acting across multiple developmental pathways.
|
|
| 33. |
- Myte, Robin, 1989-
(författare)
-
Metabolic Risk Factors and Molecular Subtypes of Colorectal Cancer
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Colorectal cancer (CRC) is a heterogeneous disease developing from distinct pathways, resulting in tumor subtypes with large differences in clinical and molecular characteristics. Molecular characteristics are increasingly being used clinically to guide therapy. However, whether molecular subtypes of CRC differ in etiology or risk factors is not clear. Clarifying such potential differences may lead to an improved understanding of CRC etiology, with implications for CRC prevention and screening.Aim: The aim of this thesis was to investigate whether risk factors related to energy metabolism, such as body fatness, and one-carbon metabolism, such as circulating B-vitamin status, were associated with specific subtypes of CRC defined by molecular characteristics of the tumor. Methods: These prospective studies are based on data and blood samples from cohorts within the population-based Northern Sweden Health and Disease Study (NSHDS). Prospective CRC cases with available archived tumor tissue were analyzed for key molecular features (KRAS and BRAF mutation status, Microsatellite instability (MSI) status, and CpG Island Methylator Phenotype (CIMP) status). Paper I was a cohort study of metabolic factors related to the metabolic syndrome (117 687 participants). Paper II was a nested-case control study on circulating insulin resistance-markers and adipokines (1010 cases and 1010 matched controls). Papers III and IV were nested case-control studies of one-carbon metabolism biomarkers and genetic variants (613 cases and 1190 matched controls).Results: In paper I, we observed associations between metabolic factors, such as BMI, blood pressure, and blood lipids, and CRC risk consistent with previous studies. These associations were similar regardless of tumor KRAS and BRAF mutation status. In paper II, circulating biomarkers of insulin resistance and adipokines were not associated with the risk of CRC or specific molecular subtypes of CRC defined by KRAS and BRAF mutation or MSI status. In paper III, higher circulating levels of metabolites involved in the methionine cycle (namely, betaine and methionine) were associated with a lower CRC risk. In paper IV, we found no support for clear subtype-specific roles of any circulating one-carbon metabolism biomarker or genetic variants in CRC development.Conclusions: The result of these prospective studies suggests that metabolic factors related to energy metabolism and one-carbon metabolism are generally associated with the risk of CRC, regardless of major subtypes defined by key molecular tumor features. If causal, metabolic risk factors likely influence the risk of colorectal cancer through more than one carcinogenic pathway.
|
|
| 34. |
- Myte, Robin, et al.
(författare)
-
One-carbon metabolism biomarkers and genetic variants in relation to colorectal cancer risk by KRAS and BRAF mutation status
- 2018
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- Disturbances in one-carbon metabolism, intracellular reactions involved in nucleotide synthesis and methylation, likely increase the risk of colorectal cancer (CRC). However, results have been inconsistent. To explore whether this inconsistency could be explained by intertumoral heterogeneity, we evaluated a comprehensive panel of one-carbon metabolism biomarkers and some single nucleotide polymorphisms (SNPs) in relation to the risk of molecular subtypes of CRC defined by mutations in the KRAS and BRAF oncogenes. This nested case-control study included 488 CRC cases and 947 matched controls from two population-based cohorts in the Northern Sweden Health and Disease Study. We analyzed 14 biomarkers and 17 SNPs in prediagnostic blood and determined KRAS and BRAF mutation status in tumor tissue. In a multivariate network analysis, no variable displayed a strong association with the risk of specific CRC subtypes. A non-synonymous SNP in the CTH gene, rs1021737, had a stronger association compared with other variables. In subsequent univariate analyses, participants with variant rs1021737 genotype had a decreased risk of KRAS-mutated CRC (OR per allele = 0.72, 95% CI = 0.50, 1.05), and an increased risk of BRAF-mutated CRC (OR per allele = 1.56, 95% CI = 1.07, 2.30), with weak evidence for heterogeneity (Pheterogeneity = 0.01). This subtype-specific SNP association was not replicated in a case-case analysis of 533 CRC cases from The Cancer Genome Atlas (P = 0.85). In conclusion, we found no support for clear subtype-specific roles of one-carbon metabolism biomarkers and SNPs in CRC development, making differences in CRC molecular subtype distributions an unlikely explanation for the varying results on the role of one-carbon metabolism in CRC development across previous studies. Further investigation of the CTH gene in colorectal carcinogenesis with regards to KRAS and BRAF mutations or other molecular characteristics of the tumor may be warranted.
|
|
| 35. |
- Myte, Robin, et al.
(författare)
-
Untangling the role of one-carbon metabolism in colorectal cancer risk : a comprehensive Bayesian network analysis
- 2017
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- The role of one-carbon metabolism (1CM), particularly folate, in colorectal cancer (CRC) development has been extensively studied, but with inconclusive results. Given the complexity of 1CM, the conventional approach, investigating components individually, may be insufficient. We used a machine learning-based Bayesian network approach to study, simultaneously, 14 circulating one-carbon metabolites, 17 related single nucleotide polymorphisms (SNPs), and several environmental factors in relation to CRC risk in 613 cases and 1190 controls from the prospective Northern Sweden Health and Disease Study. The estimated networks corresponded largely to known biochemical relationships. Plasma concentrations of folate (direct), vitamin B6 (pyridoxal 5-phosphate) (inverse), and vitamin B2 (riboflavin) (inverse) had the strongest independent associations with CRC risk. Our study demonstrates the importance of incorporating B-vitamins in future studies of 1CM and CRC development, and the usefulness of Bayesian network learning for investigating complex biological systems in relation to disease.
|
|
| 36. |
- Rutegård, Martin, et al.
(författare)
-
Efficiency of Colorectal Cancer Surveillance in Patients With Ulcerative Colitis : 38 Years' Experience in a Patient Cohort From a Defined Population Area
- 2017
-
Ingår i: Scandinavian Journal of Surgery. - : Sage Publications. - 1457-4969 .- 1799-7267. ; 106:2, s. 133-138
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Ulcerative colitis increases the risk of developing colorectal cancer. Colonoscopic surveillance is recommended although there are no randomized trials evaluating the efficacy of such a strategy. This study is an update of earlier studies from an ongoing colonoscopic surveillance program.MATERIAL AND METHODS: All patients with ulcerative colitis were invited to the surveillance program that started in 1977 at Örnsköldsvik Hospital, located in the northern part of Sweden. Five principal endoscopists performed the colonoscopies and harvested mucosal sampling for histopathological evaluation. Some 323 patients from the defined catchment area were studied from 1977 to 2014. At the end of the study period, 130 patients, including those operated on, had had total colitis for more than 10 years.RESULTS: In total, 1481 colonoscopies were performed on 323 patients during the study period without any major complications. In all, 10 cases of colorectal cancer were diagnosed in 9 patients, of whom 1 died from colorectal cancer. The cumulative incidence of colorectal cancer was 1.4% at 10 years, 2.0% at 20 years, 3.0% at 30 years, and 9.4% at 40 years of disease duration, respectively. The standardized colorectal cancer incidence ratio was 3.01 (95% confidence interval: 1.42-5.91). Major surgery was performed on 65 patients; for 20 of these, the indication for surgery was dysplasia or colorectal cancer. Panproctocolectomy was performed in 43 patients.CONCLUSION: This study supports that colonoscopic surveillance is a safe and effective long-term measure to detect dysplasia and progression to cancer. The low numbers of colorectal cancer-related deaths in our study suggest that early detection of neoplasia and adequate surgical intervention within a surveillance program may reduce colorectal cancer mortality in ulcerative colitis patients.
|
|
| 37. |
- Rutegård, Miriam, et al.
(författare)
-
PET/MRI and PET/CT hybrid imaging of rectal cancer - description and initial observations from the RECTOPET (REctal Cancer trial on PET/MRI/CT) study
- 2019
-
Ingår i: Cancer Imaging. - : BMC. - 1740-5025 .- 1470-7330. ; 19
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeThe role of hybrid imaging using F-18-fluoro-2-deoxy-D-glucose positron-emission tomography (FDG-PET), computed tomography (CT) and magnetic resonance imaging (MRI) to improve preoperative evaluation of rectal cancer is largely unknown. To investigate this, the RECTOPET (REctal Cancer Trial on PET/MRI/CT) study has been launched with the aim to assess staging and restaging of primary rectal cancer. This report presents the study workflow and the initial experiences of the impact of PET/CT on staging and management of the first patients included in the RECTOPET study.MethodsThis prospective cohort study, initiated in September 2016, is actively recruiting patients from Region Vasterbotten in Sweden. This pilot study includes patients recruited and followed up until December 2017. All patients had a biopsy-verified rectal adenocarcinoma and underwent a minimum of one preoperative FDG-PET/CT and FDG-PET/MRI examination. These patients were referred to the colorectal cancer multidisciplinary team meeting at Umea University Hospital. All available data were evaluated when making management recommendations. The clinical course was noted and changes consequent to PET imaging were described; surgical specimens underwent dedicated MRI for anatomical matching between imaging and histopathology.ResultsTwenty-four patients have so far been included in the study. Four patients were deemed unresectable, while 19 patients underwent or were scheduled for surgery; one patient was enrolled in a watch-and-wait programme after restaging. Consequent to taking part in the study, two patients were upstaged to M1 disease: one patient was diagnosed with a solitary hepatic metastasis detected using PET/CT and underwent metastasectomy prior to rectal cancer surgery, while one patient with a small, but metabolically active, lung nodulus experienced no change of management. PET/MRI did not contribute to any recorded change in patient management.ConclusionsThe RECTOPET study investigating the role of PET/CT and PET/MRI for preoperative staging of primary rectal cancer patients will provide novel data that clarify the value of adding hybrid to conventional imaging, and the role of PET/CT versus PET/MRI.Trial registrationNCT03846882.
|
|
| 38. |
- Sjöström, Olle, 1973-
(författare)
-
Risk and survival for colorectal cancer in northern Sweden : sociodemographic factors and surveillance programs
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundColorectal cancer (CRC) – i.e., cancer in the colon or rectum – is one of the most common cancers both globally and in Sweden. The risk for CRC is mainly related to age, heredity, and life-style risk factors. Previous studies have also demonstrated that individuals with lower socioeconomic status (SES), living alone, or far from care facilities may have a higher risk for CRC or a worse outcome. In contrast to life-style or sociodemographic-associated risks, an inherited risk for CRC is difficult to modify. However, colonoscopic surveillance programs can be help prevent CRC in families with a known hereditary risk.The Northern Health Care Region (northern Sweden) is the most sparsely populated region in Sweden, and travel distances to care can be long. The population in Northern Sweden is on average older and has lower SES compared with the rest of the country. The impact of these sociodemographic differences on CRC in northern Sweden is not well known. AimThis thesis analyses CRC in a northern Sweden setting with regards to incidence, survival, and associated sociodemographic risk factors, including prevention for individuals with increased hereditary risk.MethodsPapers I and II, cohort studies from the Risk North database, link individual data from health care registers to other sociodemographic registers. In Paper I, the incidence, mortality, and survival for all CRC cases in northern Sweden were compared with the rest of Sweden for the period 2007-2013. Uni- and multivariable Cox regression analysis were used to assess the impact of sociodemographic factors and tumour stage on survival by calculating hazard ratios (HR). In Paper II, we analysed any association between travel time to care and CRC survival in northern Sweden during 2007-2013 using the same type of Cox regression analysis. Papers III and IV are based on a cohort of individuals with a family history of CRC, prospectively recorded from 1995 to 2012 in the colonoscopic surveillance register at the Cancer Prevention Clinic at Umeå University Hospital. In Paper III, we evaluated the cancer preventive effect of the performed colonoscopic surveillance. Observed cases of CRC were compared to a cohort estimate of cases without surveillance. Compliance with surveillance and colonoscopic quality was also analysed. In Paper IV, we examined the cost-effectiveness of the colonoscopic surveillance program in Paper III. A cost-utility analysis with a societal perspective was used and the stability of the results was tested in a sensitivity analysis. ResultsThe age-adjusted incidence in colon cancer was 12.7% lower in northern compared to southern Sweden or 35.9/100 000 vs. 41.1/100 000 person years (p < 0.01). For rectal cancer, the incidence was 10.5% lower in the north (17.6 vs. 19.7 p <0.01). In subgroup analysis, the largest difference in incidence between northern and southern Sweden was found among individuals > 79 years age (colon - 190 vs. 237 ≈ 19.6%, rectal 72.4 vs. 88.0 ≈ 17.7%). For all of Sweden, the incidence in colorectal cancer was higher in males, individuals with lower SES, or individuals living alone. In univariable analyses of survival (all-cause and cause-specific) for colon and rectal cancer patients in all of Sweden, patients with high SES or co-habiting had a significantly better outcome compared to patients with low SES or living alone. HR for death ranged from 0.60 to 0.85 in the better-favoured risk group. No differences in colon or rectal cancer survival between northern and southern Sweden were demonstrated in the univariable analysis. However, in multivariable survival analysis, all-cause survival for colon cancer patients was better in southern Sweden (HR 0.92; 95% CI 0.86 – 0.97). For cause-specific survival for colon cancer or in any analysis for rectal cancer, no differences between northern and southern Sweden were demonstrated. In analysis of travel time, no association between travel time and survival was found. In the evaluation of the colonoscopic surveillance programme, one case of CRC was observed, compared to 9.5-10.5 expected cases. Standardised Incidence Ratio (SIR) between observed and expected cases of CRC was 0.10 (CI 95% 0.0012–0.53) to 0.11 (CI 95% 0.0014–0.59. The compliance to the surveillance program was 90%. The adenoma detection rate was 14%, and 10% of the examinations were incomplete. In the cost-utility analysis, the net cost for surveillance was 233 038 €, while saving 64.8 Quality Adjusted Life Years (QALYs) compared to non-surveillance. The resulting Incremental Cost-Effectiveness Ratio (ICER) was 3596 €/QALY, ranging from -4620 €/QALY in the best-case scenario to 33 779 € /QALY in the worst-case scenario.ConclusionThe incidence of CRC was lower in northern Sweden and most evident in the elderly, raising questions on differences in life-style between northern and southern Sweden in the past. There were considerable sociodemographic disparities in CRC survival in Sweden, including a lower all-cause survival for colon cancer patients in the north. In this study, travel time to care in northern Sweden did not affect survival and the lower all-cause survival in northern Sweden cannot be fully explained. The colonoscopic surveillance of families in northern Sweden with inherited risk for CRC had a good cancer preventive effect, including a high cost-effectiveness. The reasons for the good effect may be high compliance, since the quality of the colonoscopies was moderate.
|
|
| 39. |
|
|
| 40. |
- Svenson, Ulrika, et al.
(författare)
-
Telomere length in peripheral leukocytes is associated with immune cell tumor infiltration and prognosis in colorectal cancer patients
- 2016
-
Ingår i: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 37:8, s. 10877-10882
-
Tidskriftsartikel (refereegranskat)abstract
- Telomeres are protective structures at the end of chromosomes, essential for chromosomal integrity. A large number of studies have investigated leukocyte telomere length as a possible risk marker for various cancers, colorectal cancer (CRC) included. In contrast, studies investigating leukocyte telomere length in relation to CRC survival are lacking. We previously reported that relative telomere length (RTL) of leukocytes collected at diagnosis predicted survival in patients with breast and kidney cancer. We suggested that these findings might reflect various immunological mechanisms, affected by the presence of a tumor. In the present study, leukocyte RTL was examined in relation to immune cell tumor infiltration and prognosis in 130 patients with CRC diagnosis. RTL was measured with a well-established qPCR method. We found that patients with the highest degree of lymphocyte tumor infiltration had shorter leukocyte RTL. Consistent with our previous findings, short RTL was a favorable prognostic marker in univariate survival analysis. In the current study, RTL did not remain as an independent predictor in multivariate survival analysis, when including metastatic status in the model. However, a non-significant trend towards a similar telomere-associated survival pattern was observed in patients with limited disease. In contrast, for patients who died of other causes than CRC, short RTL was associated with significantly shorter survival time. To our knowledge, this is the first study to investigate an association between leukocyte RTL, immune cell tumor infiltration, and cancer-specific survival in CRC patients. Larger studies are warranted to verify these findings.
|
|
