Crossover almost by definition causes some level of confoundment. There are reasons to believe confoundment may not be as strong here. The latest one relates to the recent recurrent trial design where no temodar is used. When a patient only gets temador after chemo-radiation, their lymphocyte count typically goes down. If you have temodar+ DC therapy, the lymphocyte may not be negatively affected to as critical of a degree. However, getting someone's lymphocyte count back up after long chemo treatment may be difficult. This may put placebos in the current trial at a disadvantage -- maybe, and possibly why the new recurrent trial does not use Temador. Anyway, there are many considerations. IMHO
There are also reasons to think there may be confoundment to some degree, because the principal investigator is seeing what seems to her as all the people in the trial living longer than expected. This may not in fact be "all" the patients, because some patients left the trial and started other trials or therapies. IMHO
You have to look at everything very closely.