View Full Version : "Median survival"?
Mon Apr 5, 2010, 03:07 AM
Hi you all,
recently I have been reading in the posts concern over survival times.
While reading literature, it seems that the survival is in "median survival", which would mean not all the concerned...
For example in the following Treatment and prognosis of the myelodysplastic syndromes, (http://www.uptodate.com/home/content/topic.do?topicKey=leukemia/9134) and the following (Blood, Vol. 89 No. 6 (March 15), 1997: pp. 2079-2088)
International Scoring System for Evaluating Prognosis in Myelodysplastic Syndromes ,
they are clearly writing median. If I understand this correctly, and please advice if I do not, this would mean 50% have succumbed in the given number of years; not all. The other 50% is living much longer :)
Mon Apr 5, 2010, 04:25 AM
You are correct, although you should say "The other 50% is living longer", since it's not necessarily "much longer".
When they refer in that article to a "number of studies" and say "those with RA and RARS had median survivals of approximately three to six years" it means that: In at least one study half the people survived less than three years and half survived more than three years.
In at least one study half the people survived less than six years and half survived more than six years.
In all the other studies, the 50% point was somewhere between three years and six years, i.e., three years was the worst median among the studies and six years was the best median among those studies.
I'm not sure why they add the word "approximately" since it's already a range.
What it doesn't tell you is how long people survived above (or below) that average, i.e., the best and worst outcomes for individuals. How long beyond six years did half the people in a study survive? Seven years? Ten years? Even longer?
That's the trouble with a brief report of statistics: you never know what it really means for you, or any other individual.
As patients we also learn that statistics tend to give us a pessimistic view because they are based on patients treated years ago, before many of the current treatments were available or the best dosages of drugs had been found. Outcomes are better and better each year, and the statistics we read will eventually catch up. Until then, the statistics give us a rough idea how serious these diseases are but not the state of treatment and survival today, and they don't tell us what will happen to any of us individually.
Mon Apr 5, 2010, 06:17 AM
Thank you Neil.
That is what I was wondering, especially the "tails" that we do not know about. And, like you pointed out, the statistics are history, actually what happened to a number of people years ago, so directly it is not a personal prediction for anybody. And I suppose one never knows, either way. Also I understand that most MDS patients in statistics are over 60 years; for a 60-year old twenty or even 10 years is quite different from somebody in their 30's.
But I suppose the doctors need something to go by, balancing safety and survival, risk in different ways. Even aspirin carries its risk, but it is not great; but the perceived benefit is greater. Well, at least for most of us.
I actually have tried to find out what happens to long-living MDS people - how long is the longest? I have not found information, mostly on the high-risk ones.
Or, if people jump from one category to another, how do they fit into statistics? Oh the joy of statistics!
Mon Apr 5, 2010, 01:03 PM
As you can read in this article from 2005 "MDS with isolated erythroid lineage dysplasia identifies a subset of truly low-risk patients, whose survival is significantly affected by demographic variables rather than by disease features. The life expectancy of such patients aged 70 years or older is not significantly shorter than that of the general population."
This means that patients with Refractory Anemia that get their dx when they are 70 years or older can live just as long as persons without MDS :).
One year ago I participated in a patient forum for MDS patients in Stockholm and met several RA patients that had had their disease more than 20 years. They only got Aranesp or similar drugs and were symptom free.
The patients in statistical reports are classified into the the group they belonged to at dx even if they will belong to other categories later.
71 yo, dx MDS Interm-1 May 2006, transfusion dependent, Desferal and Exjade for iron overload, Neupogen 2 injections/week for low WBCs, asymptomatic.
Mon Apr 5, 2010, 03:04 PM
Thank you Birgitta.
That makes me feel a lot better. It is sometimes recking on the nerve not knowing where to belong, so to say, uncertainty of yes-no, suspected but not confirmed, also not released.
I have heard twice already, ten years apart, that if it was serious, I would have passed away long time ago. What that "it" was, was not specified.
Now I know that I am suspected, or perhaps one of these mild cases.
So I should be :) because I am still here wondering about it!
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