Survival Data Analysis

Survival of what exactly?

You could try an exponential N=A*exp(-Bt) as used for radioactive decays, with N the nu,ber of survivors.

A logistic function if the numbers of deaths show a normal distribution in time, like for car spare parts.

http://en.wikipedia.org/wiki/Logistic_di stribution

2006-05-23 05:56:06 by eazy_eazyy

DataClinic Information On Biostatistics Consulting Techniques Survival Analysis. www.dataclinic.org

i need to perform data analysis on the study so need data from the study, someone please help

Baseline results:
http://www.lipidsonline.org/slides/slide 01.cfm?q=Scandinavian+Simvastatin+Surviv al+Study
http://en.wikipedia.org/wiki/Scandinavia n_Simvastatin_Survival_Study
http://dic.academic.ru/dic.nsf/enwiki/15 1775

If you need more details, in the net you find several sites offering a free download or free trial of the complete publication.

2009-02-12 15:06:27 by adi

Price: $87.20

Hi
I am doing a statistical data analysis on cancer treatments for Small Cell Lung Cancer.
I have two groups (A and B), and 2 drugs (P and E). Both Groups are given both drugs, but group A is given drug E then drug P, and Group B is given drug P then drug E. So there is a difference in the regimens of the drugs given which are being compared.
The data sets are the number of days the patients have survived either on regimen A (drug E then P) or regimen B (drug P then E).
Some of the data is right censored e.g. a patient who has survived 765 days and continues to live after the study is terminated has the survival time recorded as 765+, meaning the patient has survived beyond 765 days.
Also, because the patients did not begin the treatments at the same time the censored data all have different values. For example, one patient may have survived 765+ days and another may have survived 256+ days.

What I am trying to find out is if there is any difference in the average survival time between the two treatment regimens.

My questions:
1. how do I treat the censored data? Do I just ignore the "+" and use, for example, use 765 days
instead of 765+ days in my analysis? If not, should I calculate the the survival rate and estimate when the patient is expected to pass away?

2. Am I correct in saying that I need to test for the equality of means between group A and group B? If so, what test should I use? (ANOVA or a T-test? Or some other test?) Also, the number of observations in the groups are not equal. Group A has 62 observations and Group B has 59 observations.
3. Can anyone tell me how to make a box plot in Excel? Preferably, side by side box plots.

Please Note:
This is not for a real analysis of cancer treatments or regimens, but is for an assignment.
Also, all of my analysis must be done in excel, so please don't tell me to plug my data into SPSS or another statistical software program.
Also, this assignment is for a first year, undergraduate, statistical computing class, so please understand that my statistical knowledge is rather limited, and also that this assignment has more to do with being able to show that I am able to do a statistical analysis in Excel, than showing my statistical abilities (obviously to a certain extent) and bio statistics.

Any help would be greatly appreciated. Thanks :)

It would be helpful to know more specifically what your statistical background is, especially whether you have studied any survival analysis. A simple graphical summary would be a Kaplan-Meier plot (google it) - they're quite simple to make even if you haven't studied survival analysis.

If you haven't learnt any techniques to deal with censored data, my advice would be to leave them out as long as there aren't too many. This will obviously bias your results, but it's a better solution than ignoring the +.

You could then just do a (unpaired) t-test on the remaining survival times, comparing the two groups. It's a little crude but should give something interesting. The unequal sample sizes doesn't matter for unpaired t-tests.

Obviously, if there are marks for it, it would be well worth commenting on all the assumptions you have made etc.

HTH

2009-11-17 23:18:16 by sally

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interpreting data and statistical analysis of survival curves in clinical trials

I hope this link I'm including helps, as I certainly can't explain it much better, I do beg your pardon.

http://www.shortenurl.com/2bkng

2008-05-11 13:06:13 by khaled f

Cancer Survival Rates Improving Across Europe, But Still Lagging Behind United States


Zosia Chustecka
Information from Industry


October 15, 2008 — New reports from EUROCARE suggest that cancer care in Europe is improving and that the gaps between countries are narrowing. However, comparisons with US statistics suggest that cancer survival in Europe is still lagging behind the United States.

One of the main messages from both reports is that in Europe, "for most cancers, survival has increased and between-country survival differences have decreased over time," notes an accompanying commentary by Mike Richards, CBE, from the United Kingdom's Department of Health. However, the differences between countries are not trivial, and "many more lives could be saved if the outcomes of all countries were brought up to the standards of the best" (ie, Norway, Sweden, and Finland), he comments. The United Kingdom in particular comes out badly in the tables, showing cancer survival rates that are among the worst in Europe. The findings suggest that the national cancer plan for England, which began in 2000, is not working, a second editorial comments.

Survival Rates Significantly Higher in United States Than in Europe

One of the reports compares the statistics from Europe with those from the United States and shows that for most solid tumors, survival rates were significantly higher in US patients than in European patients. This analysis, headed by Arduino Verdecchia, PhD, from the National Center for Epidemiology, Health Surveillance, and Promotion, in Rome, Italy, was based on the most recent data available. It involved about 6.7 million patients from 21 countries, who were diagnosed with cancer between 2004 and 2006.

Survival was significantly higher in the United States for all solid tumors. The greatest differences were seen in the major cancer sites: colon and rectum (56.2% in Europe vs 65.5% in the United States), breast (79.0% vs 90.1%), and prostate cancer (77.5% vs 99.3%), and this "probably represents differences in the timeliness of diagnosis," they comment.

Further analysis of these figures shows that, in the case of men, more than half of the difference in survival between Europe and United States can be attributed to prostate cancer. When prostate cancer is excluded, the survival rates decreased to 38.1% in Europe and 46.9% in the United States. For women, the survival rate of 62.9% for all cancers in the United States is comparable to that seen in the wealthiest European countries (eg, 61.7% in Sweden, 59.7% in Europe), and the slightly higher survival in the United States was largely due to better survival for colorectal and breast cancer, the authors comment.

Lancet Oncol. Published online December 21, 2008.

It really is not a fair comparison. Europe is made up by several countries, we are just one. We have a standard of care which is the same regardless of what state you are in. you cannot expect the standard to be the same in each country the makes up Europe.

The story states it may be due to differences in the timeliness of diagnosis, which may be true. It would be easy enough to figure out, just compare the data by stage.

2009-02-04 14:14:57 by Mary J