- Roman Mezencev added an answer:I have a question regarding SEER database. Can anyone help me how to compare two survival graphs derived from SEER database?
SEER database has epidemiological cancer data from US. It has its own software that gets incidence rates from the database and also gives the survival graph from the database.
After getting survival graphs for two different study cohorts I am not sure how to statistically compare them and get a p-value for the comparison.
can anybody please help and give me some suggestions.
Babu: In SEER Survival Session you need to check the box "Case Listing" in the "Parameters" tab. Than you need to define all your analysis variables as required by your project (site, age, sex etc...) and hit the "Execute" button and you will get the table with single line for every individual. The most important columns from the table will be "Survival Months" and "Vital Status Recode". You can use highlight all-copy/paste commands to get the data into Excel, save it in whichever format is needed and process by a statistical SW of your choice for tests that I mentioned above (after coding for dead/censored individuals vs time between diagnosis and follow-up).Following
- Mona Ellaithi added an answer:Why is oesophageal adenocarcinoma increasing?
Over the past three decades, adenocarcinoma of the oesophagus has increased in incidence more than any other tumour. The cancer is thought to be the result of gastroesophageal reflux damaging and inflaming the distal oesophagus and causing its squamous mucosa to undergo columnar metaplasia . This Barrett’s mucosa has an increased risk of progressing to dysplasia and adenocarcinoma.
What factors are responsible for the rapid rise?
The rising of adenocarcinoma of oesphygous is more common in westren world. It has been connected in many studies with type of diet in wetren world. As Olivier mentioned to you maybe with the rising of obesity and changing in diet we will see adenocarcinoma raise in countries were we used to see SCC more common. However I doubt that will happen with the increase in socioeconomic status. Moreover and based on my observation oesphygeal cancer is more connected with occupation.Following
- Mona Ellaithi added an answer:Can someone help me with the incidence or prevalence of Burkitts lymphoma in African countries or Nigeria?
Need some prevalence data on Burkitts Lymphoma
Go to GLOBOCAN data published by IARC.Following
- Rajshree Dayanand Katke added an answer:What is the incidence of huge ovarian tumours in Adolesent girls?
Rdeently I operated on a young girl of 16 yrs,with huge mass in the Abdomen.on CT scan revealed of Large ovarian tumour extending all over abdomen probably of neoplastic etiology.all tumour markers were in normal range.huge rt.ovarian tumour of 4.5 kg taken out.frozen showed cystadenoma of ovary provisionally benign.final histopath awaited.how often one can say such huge ovarian tumours in Adolesent girls ?
sir Asharaf tumours histopathology report came as Benign ovarian tumour.patient went home attending school.Following
- Kristian Svendsen added an answer:Are there any suggestions for creating a nomogram for the prediction of cancer patient survival?
Is there anyone that can give me some suggestions? I normally use Stata for my analyses. Thank you.
I Guess you might have seen this already http://www.stata.com/meeting/spain13/abstracts/materials/sp13_zlotnik.pdf In short there is a way in Stata to create nomograms based on regression results but this presentation at least does not point to a ready-made package to download for sure. (Nomograms can vary a lot in how it looks and how many variables etc are used.)Following
- Julie Cwikel added an answer:How can public concern regarding a risk-related problem or issue be measured over time, without conducting a survey?Methodology question: I am trying to figure out how to measure the degree to which a risk-related problem has become a public issue. The metric needs to be easily analyzed, accessible, quantitative, and stable over at least five years (from 2015 to 2020) and have high face validity. The measurement should be robust – it does not have to be particularly refined or capable of resolving small differences.
The application for this metric is that I am developing a project that has to do with factors (such as Peter Sandeman’s “outrage”) that determine which risk-related (environmental, health, sustainability) issues become public issues over time. I need a way to measure outcomes and compare them against predictions.
Social media is the most obvious approach. One metric would be Google hits, which is convenient, free, and cumulative, and which almost certainly will be around in five years in roughly the present form without too much bias from algorithm changes introduced over the period. On the other hand, I am concerned about Twitter because I’m not sure it will be as stable a platform over the time period and I’m not sure how much people tweet about issues as opposed to people and events. Newspaper inches in a journal of record (such as the New York Times), which used to be an old standby, might be completely obsolete by 2020.
I would be grateful for practical ideas.
We once contemplated a study of the salience of public health issues (in our case stress related) that were loaded up and viewed on u-tube. This can be monitored if you have a good tech person. Another metric to think about Tee.Following
- Jignasa Sathwara asked a question:What is the scope of the emerging field of "cancer pharmacoepidemiology" in India?Future scope of pharmacoepidemiology in India.Following
- Paul A Macmullan added an answer:Is there any known anticorrelation between cancer and autoimmunity?As a possibly pathway to understanding the role the immune system plays in attempt to control cancer growth, an interesting test would be to perform an epidemiological study of those with autoimmunity diseases and find the incidence of cancer in that sub-population.
Are cancer rates lower in those with some form of autoimmunity? Have studies been carried out to test this?First of all, apologies for late reply. Was cleaning up my email when I came across this.
The short answer is Yes. In SLE , while there is a higher risk of certain cancers such as lymphoma, a disease which predominately effects women, the risk of both ovarian and breast cancer is dramatically reduced.
Why? well thats a different story.........Following
- Gilbert L'Italien added an answer:What is the best approach to adjust for smoking as a potential confounder?I want to adjust for smoking in an analysis and want to go beyond the simple current, former and never categorization of smokers, which seems to be a bit too crude for my purposes. Of course, the choice of how to parameterize smoking status depends on the outcome of interest (here, my outcome is composite cardiovascular disease). I am thinking that I need to account for dose/duration and perhaps recency of quitting. I am wondering what advice people have and if there are any key references that specifically address this issue.Agree that smoking duration is more important than pack years. In my view the deleterious effects of smoking on CVD pertain to artherothrombotic effects and are cumulative. But those effects diminish over time with stopping. So classify smokers as current (smoking during the period of follow up for CVD events) or past (quit smoking before the period of follow up for CVD events) or recent (quit smoking during the period of follow up for CVD events). Add another variable that gives the duration of smoking (eg 5 years). If you have a large enough sample size, you could also add a variable for age at onset of smoking.
As an example, I smoked for 6 years, I began smoking at age 18, I am now 63.
So class me as past smoker , 6yrs duration, age of smoking onset 18. These variables would exert very little effect on my current risk for CVD, which is what you wish (ie dose response). A current smoker, who smoked for 20 years, who started at 18 and is currently 38 should exhibit a much higher risk for CVD than a non smoker of similar ageFollowing
- Gurdeep Singh Mannu added an answer:Is the increase in DCIS incidence over the last few decades solely due to the introduction of breast screening?To what extent have lifestyle, diet, patient, treatment and tumour factors influenced this change (if at all)?Thank you Constantine, that is a most informative contribution. Thank you Narender, however I have found ultrasound is rarely used in some centres for screening purposes in the screening age group (>40) (with mammography preferred) but I agree other factors such as urbanization and lifestyle that you mention may be important.Following
- R. Bruce Paton added an answer:What is the scientific grounding for sustainability? Is there such a thing as "sustainability science"?Writing a book and one chapter is on how managing sustainability seems to be turning into a profession, with full-time managers doing this in business. What do professionals in sustainability need to know? Is there a distinct science underlying the field? If so, what does it involve? Are environmental sciences and studies programs providing adequate grounding in this science?
Please concentrate on the questions, not the definition of sustainability. There are lots of different definitions of sustainability (my book will offer another one), but for the purpose of this discussion, please assume that "sustainability" means doing business and managing enterprises in a way that works toward the goal that there is minimum impact on the environment, good prospects for the future, no degradation that would compromise the future, and that protects health and a decent life.for an insightful framing of the scientific questions, look at The Natural Step's "system conditions" for sustainability. The Natural Step seems to be somewhat out of fashion among Americans working in this area, but the framework is immensely valuable conceptually.Following
- Mojca Bozic-Mijovski added an answer:Determing cut off value to consider as risk while calculating odds ratioHow to determine cut off value of independent variables (e.g. pack year of smoking, parity, amount of alcohol etc.) to consider as risk while analyzing OR in case control study.I absolutely agree that continuous variates should be used as often as possible. However, for researches as myself (I'm a biochemist with no access to statisticians), calculating an odds ratio is much simpler.
I just surfed the net trying to find how to plot log odds (for example log odds of developing cardiovascular disease against number of cigarettes smoked daily) and found absolutely nothing useful.Following
- Kota Katanoda added an answer:How can I calculate risk-factor-specific incidence rates from overall population incidence rate and prevalence/relative risk of that risk factor?I am looking for a standard way to calculate risk-factor-specific incidence rate from overall population incidence rate. The available data are overall population incidence rate of a disease, prevalence of a risk factor, and relative risk of that disease according to the risk factor. What I want to do is to estimate the incidence rate of people with or without that risk factor. My image is to allocate the overall incidence rate into two groups (risk factor holders and non-holders), keeping consistency with the overall incidence rate. Are there any good references?Thanks Freddy! That's exactly what I was looking for.Following
- Suman Saurabh added an answer:How to calculate the the confidence intervals for a Mantel Haenszel stratified Odds ratio?I am synthesizing some data from a few observational studies for a meta analysis later, I calculated a weighted odds ratio using the M.H method, however I am not sure how to calculate the confidence intervals. I am not using any statistical software at the moment, just doing calculations and putting in the data into an excel file. Can I just calculate the standard error by adding all exposed and unexposed groups in the cases and controls, and then using the standard formula for standard error calculation and so on for C.I ? Or is there any specific method for calculating C.I of the M.H odds ratios.A specific method for calculating confidence interval of Mantel-Haenszel Odds Ratio was first described in Clayton D. & Hills M. (1993) Statistical Methods in Epidemiology. Oxford University Press, Oxford. It is also reproduced in Page 183 of Essential Medical Statistics by Betty Kirkwood and Jonathan E. Sterne. The following steps should be followed to calculate the Mantel-Haenszel CI :
i) Here 95% CI ranges from OR/EF to OR*EF, where OR is Mantel-Haenszel Odds ratio and EF is the exposure factor;
ii) EF = exp (1.96* SE) , where exp is exponential and SE is the Standard error of the Mantel-Haenszel Odds Ratio;
iii) SE = Sqrt [V/(Q*R)];
iv) Now just think about a, b, c, d as the values the four cells of a 2 X 2 table of each stratum (Remember that using this approach we usually describe the simple Odds Ratio as (a*d)/ (b*c) ). Thus ai, bi, ci ,di represent the a, b, c, d values of the i-th stratum. Similarly ni is the sum of ai, bi, ci and di in the i-th stratum;
v) Using the above notational style,
Q = Sigma (i.e. summation of) [(ai*bi) / ni]
R = Sigma [(ci*di) / ni]
V = Sigma [(ai +bi)* (ci+di)*(ai+ci)*(bi+di)]/ [ni*ni*(ni-1)].
You can easily generate the 95% Ci in Excel itself provided you carefully translate the above to Excel formula. If you are still not sure, you can directly consult the books mentioned in the beginning.Following
- Rute Barbosa Marques added an answer:Intermittent Androgen Deprivation (IAD) therapy in prostate cancer patients: Do you know the degree of implementation in your country or area?At least since 2008 IAD has been considered an option that may be offered to men with metastatic prostate cancer but I have no idea about actual application of this strategy. Any feedback or publications would be welcomed.You may find this article interesting.
- Tom Nadarzynski asked a question:Would targeted (risk-based) HPV vaccination for men who have sex with men be considered in the absence of gender-neutral HPV vaccination?Could that be considered in countries with high coverage in females due to the low anticipated benefit and insufficient cost-effectiveness? There are MSM-targeted hepatitis vaccination programmes already in place in some countries such as the UK.Following
- Jason Leung added an answer:Calculating standard error of a log Odds ratio from confidence intervals?Higher limit of C.I - lower limit of C.I / 3.92 is the formula I used, my question is that this gives me a standard error of the regular odds ratio as opposed as the Log odds ratio, so should I just calculate the natural log of the standard errors I get through the above formula or should I first convert the limits of the confidence intervals into their natural log and calculate the S.E then?For your formula, higher limit and lower limit of Ci should be taken natural log first
e.g. CI of OR (2, 5), after taking natural log, it is (0.693, 1.609),
remark: 3.92 is 1.96*2Following
- Krzysztof Lach added an answer:With limited data available how do we explain inter-study heterogeneity while doing a meta-analysis?I am trying to look at the association between a polymorphism and risk of cancer incidence by a meta-analysis. However for some studies we do not have the complete genotype information for the same. We noted allele distribution from the publications and tried to contact authors to obtain the complete genotype data. Some of them, however, haven't responded. So we have done a primary analysis including only studies that have the complete genotype data. Now I wish to do a sensitivity analysis by including the omitted studies and perform the comparisons with the available data. Is this approach correct? or unnecessary?The question is how will you manage to add the studies, from which results are not available? From my perspective the best thing you can do is to discuss possbile limitation of publication bias. You are aware that the estimation done by metaanalysis could be different because of unpublished results. The issue has to be discussed and explained. Stats Direct shows a plot, from whoch possible publication bias can be assessed, although you know for shure that there is not available data, because you encountered such studies. On the other hand, if the result of the metaanalysis shows a heterogenity test p<= 0,1, that could mean possible heterogenity of the studies included to metaanalysis. Then a sensitivity analysis is a must taking into account discriminating factors. More on that topic here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767262/Following
- Sylvia Wassertheil-Smoller added an answer:What do you think abut the USPHS task force recommendations on mammography and prostate caner screening?What do you think abut the USPHS task force recommendations on mammography and prostate caner screening?Thanks. Yes, I would be interested in a citable PDF version so that I can send it to some course leaders and students and start a debate on this in the medical school.Following
- Brkic Tomislav added an answer:What is the incidence of colorectal cancer in the differents parts of colon?I've been studying in some books and found differents values, none consensus.Tumor subsite location within the colon is prognostic for survival after colon cancer diagnosis. Proximal colon cancers are more likely to present with advanced stage than distal cancers. Sigmoid colon cancers were observed to have earlier stage, lower tumor grade, and independently decreased colorectal cancer-specific mortality compared with proximal tumors.Following
- Asif Patel added an answer:Does anybody know where to get good stats on worldwide epidemiology of thyroid cancer over last 10-20 years?Thyroid cancerI think you could get it if you contact or emial WHO. You can try even Lancet.Following
- Alireza Mosavi Jarrahi added an answer:How can we use capture-recapture analysis for evaluating our cancer registry data?We are planning to evaluate the quality of our cancer registry data for its completeness by using 3 sources of data, is there any one who would like to help us in capture-recapture analysis?You need to make sure you understand the underlying assumption of capture-recapture. In the R library there are few packages that will help you to do the analysis.Following
- Carol Gano asked a question:Non-tomato sourced "FruHis" in dried fruits.Epidemiology links processed tomato lycopene with reduced risk of prostate cancer, is anyone doing research on non-tomato sources of "FruHis" a reported potential "co-factor" that may explain why other foods rich in lycopene do not display the characteristic reduction in prostate cancer risk?Following
- Barry James Barclay added an answer:Cancer and waterCancer Risk,Environment,Contaminated Drinking Water.
Women have increased risk of cancer 20 years after drinking and using slightly contaminated water (which was officially - according to all formal criteria - considered safe and of proper quality).
Although water is important as a vector for environmental carcinogens in many cases the contaminants are organic ( pesticides like malathion) and bioaccumulate in human adipose tissue -like those of the breast. Secondly many water-soluable contaminants are found in high concentrations in foods even when water remains potable.Following
- Closed account asked a question:Preventing Cancer. WaterCancer Risk,Environment,Contaminated Drinking Water.
at that site (above) : New interesting scientific information: A relevant presentation was made at University of Massachsetts, Amherst, October 22, 2010: (So-called EWRE seminar). The seminar was presented by Dr. Verónica Vieira from School of Public Health at Boston University about “Cancer Risk and Environmental Exposure to Contaminated Drinking Water”. The site shows the ABSTRACT.
About Cancer Epidemiology
A forum for discussions about the epidemiology of cancer.