It was about what happens given that patients remain in remission or do not experience any events then how is their outlook going to change. The motivation behind this study was there have been some studies about this in systemic diffuse large B-cell lymphoma and in systemic diffuse large B-cell lymphoma it’s shown that patients who survive around two years without experiencing an event have survival prospects which are very, very similar to that of a healthy population. However, primary CNS lymphoma relies on different treatments because the blood-brain barrier restricts the administration possibilities of chemotherapy. So it’s expected that they tend to perform a lot worse than the ones we see the survival actually improve over time compared to how the background population has performed and, if so, to what extent and does it ever normalise.
The probability of surviving five years without relapsing is about 25% when you look at it from diagnosis which is quite bad compared to normal diffuse large B-cell lymphoma. However, given that they survive one or two years this actually increases to around 50% so there is a big increase but it’s still not a great prospect to have. Similarly, even if you condition on later time points of being an event free survival or remaining in remission for, for example, two or three years, it does not really improve that much past this prospect of having a five year probability of surviving without relapsing of around 50%. So it improves but it does not improve that much. Furthermore, if you’re looking at the loss of life expectancy we also see there that initially if you follow patients for about five years they will be expected to lose about two years of life expectancy compared to the general population but among patients who survive or reach at least one year or remain in remission for at least one year then we see that this reduces to about one year. So there’s a big reduction but it’s definitely still increased compared to the general healthy population.
The main take home message from this study is that patients definitely do better over time so there is a bit of reassurance that the longer you remain in remission the better your prospects are going to be but there has to be a decent follow-up programme because they are still at increased risk of events of all kinds and all sorts.