vitamin d/calcium and lung cancer group presentation
TRANSCRIPT
7/27/2019 Vitamin D/Calcium and Lung Cancer group presentation
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J E S S I C A G R A T I G N Y
S I L A S H A R N E S S
L I N D S E Y O W N B Y
M O L L Y C H A F F I N
J E N N I F E R B A I L E Y
Cancer
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Cancer Today
Cancer can be described as uncontrolled growth of abnormal body cells. Cancer occurs when cellularDNA is damaged, but the cell does not repair itself or
die but continues to reproduce unneeded cells.
7/27/2019 Vitamin D/Calcium and Lung Cancer group presentation
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Cancer Today
Cancer is the 2nd leading cause of death in the USA
Accounts for nearly 1 in 4 deaths
Lung cancer Greatest risk factor is cigarette use and other tobacco-related
products
Accounts for about 14% of cancer diagnosises
Largest percentage of cancer-related deaths (~27%) Death rates have decreased since the early 1990’s
American Cancer Society http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-036845.pdf
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Methods of Cancer Prevention
Healthy lifestyle
Diet
Variation and moderation
Lifestyle
Decreased alcohol consumption and tobacco use
Physical activity
Each year, more than 572,000 Americans die of cancer; about one-third of these deaths are linked topoor diet, physical inactivity, and carrying too much
weight.
American Cancer Society http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-036845.pdf
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Current Methods of Cancer Treatment
Surgery
Chemotherapy
Radiation
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Vitamin D and Cancer Overview
1,25-dihydroxyvitamin D has been shown to decreasetumor invasion, metastasis, and angiogenesis inmany cancer models of tobacco-related cancer
Tobacco smoke chemicals may influence vitamin Dmetabolism and function, and conversely vitamin Dmay modify the carcinogenicity of tobacco smokechemicals
Reduced concentrations of vitamin D are associated with increased proliferation, decreased apoptosis,and inhibited differentiation in cells
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Calcium and Cancer Overview
Although the exact mechanism is unclear, Calciumsupplementaion has been shown to decrease the risk of cancer.
According to the National Cancer Institute, Calciummay indirectly reduce cell proliferation and improvecell signaling, causing cancer cells to differentiateand/or die.
http://www.cancer.gov/cancertopics/factsheet/prevention/calcium
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Introduction of Tobacco-Related Study
Study design
Population
n=
Duration Follow-up method/time
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Objective for Tobacco-Related Cancer Study
Tobacco smoke chemicals may influence vitamin Dmetabolism and function, and conversely vitamin Dmay modify the carcinogenicity of tobacco smokechemicals
Hypothesis: lower plasma 25-hydroxyvitamin D[25(OH)D] is associated with a higher risk of tobacco-related cancer in the general population
The endpoint of this study was incident tobacco-
related cancer Ascertain information on other cancers
The most common cancer associated with smoking is lung
7/27/2019 Vitamin D/Calcium and Lung Cancer group presentation
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Maybe insert Table 1 from the study here?
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Method for Tobacco-Related Study
Method of selection
Plasma sample collection method
Questionnaires
Tobacco consumption Alcohol consumption
Lifestyle
BMI
Statistical analyses Cox proportional hazards regression (95% CI)
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Results from Tobacco-Related Study
Associations with low 25(OH)D
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Insert Table 2?
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Possible Limitations
Participant bias
Degree of sun exposure Seasonal variation
Delay in measurement Residual confounding Observational shows no causality, only associations
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Strengths of the Study
Homogenous population
28 year follow up
Detailed smoking history
Strong statistical power
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Significant Findings of Tobacco-Related Study
Lower concentrations of 25(OH)D were associated with a higher risk of tobacco-related cancer but notother cancers
Biologic plausibility Smoking is associated with reduced 25(OH)D
concentrations Reduced concentrations of vitamin D are associated with
increased proliferation, decreased apoptosis, and inhibiteddifferentiation in both normal and neoplastic cells
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Introduction of CaD RCT
Study design
Population
n=
Duration Follow-up method/time
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Objective for CaD RCT
Associations have been established for high calciumintake and reduced cancer risk. Luminal effect of high calcium intake provided a plausible
mechanism
Determine the efficacy of calcium alone and calciumplus vitamin D in reducing incident cancer risk of alltypes Null hypothesis was that there would be no difference in all
cancer incidence between the 3 calcium and vitamin D txgroups
The primary outcome was fracture incidence and theprincipal secondary outcome was cancer incidence
7/27/2019 Vitamin D/Calcium and Lung Cancer group presentation
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Method for CaD RCT
Recruited on a population-based sample
Random telephone dialing of all listed numbers in the counties
Inclusion criteria
Subjects were randomly assigned to receive 1,400-1,500 mg supplemental calcium/D alone (Ca-only),supplemental calcium plus 1,100 IU vitamin D3/d(Ca + D), or placebo
Serum samples taken Primary designed endpoints of the study concerned
skeletal status and the calcium economy
7/27/2019 Vitamin D/Calcium and Lung Cancer group presentation
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Methods of CaD RCT
Statistical analyses
Survival analysis used to plot and evaluate differences incancer incidence
Various logistic regression models were developed to estimate
relative risk of being in the cancer group at conclusion of thetrial and to explore the determinants of observed rates of cancer incidence
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Results of CaD RCT
50 women developed nonskin cancer during thecourse of the study 13 in first year
37 thereafter
Table 1 While the findings for the effect of vitamin D are not
considered a chance association, it is uncertain whether the marginal calcium effect represents a
chance occurrence Few other calcium trials have cancer outcome as the endpoint
Explain the possible method of calcium on cancer tx
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Significant Findings of CaD RCT
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Strengths of CaD RCT
Population based
Low drop out rate
High level of tx adherence (compliance)
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Weaknesses of CaD RCT
Cancer was not the principal outcome variable
Mechanisms are not well known at this time
Several of the effects of vitamin D in cancer model
systems require concentrations of of calcitriolsubstantially higher than can be achievedphysiologically in intact humans aw3
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Conclusion from Studies
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Unsolved Problems in Cancer Research
No cure
Tx is hard on patients
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Future Research Needed
Understand tx mechanisms
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Take Home Message
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Sources