I may have read into that perceived benefits differently than everyone.
I always thought that it meant more for the patients perception. For instance, even though the low dose may not have any effect at all on the cancer the patient may perceive the trial as a ray of hope and wish to continue especially if they are not experiencing any negative side effects.
This perception puts the patient in a better metal state which I am sure we all know that our physical health has a lot to do with our mental attitude.
I just thought that was what they were referring too.