Thanks Flipper44 for your words and feedback. I agree with you that the lost to follow could have been found afterwards or distributed. It's just that I think is more probable that the majority were not found after all that time. And because of that, my theory is that they were just taken out of the study. I also think that, because apparently we don't have censors in the DCVax-L arm final results for the first 2 years.
I think I should have written a little bit different and it is that the 13 could have been part of the crossovers or of the non crossovers, but then just taken out of the study because they were lost to follow and maybe from the earliest part of the trial. What I don't know is why those lost to follow could have been taken out of the study, could it be something a RA asked them to do that for being part of the earliest time of the trial?