Can the trial be stopped without me?
Yes, and that is a protection. An independent board watches the results while the trial runs and can stop it if the treatment is clearly harming people.
They can also stop it because the treatment is clearly better, since it would be wrong to keep it from the other group. Either way you must be told, and told what happens to your care next.
Written by two physicians. Checked against patient information from the US National Cancer Institute and Cancer Research UK.