It doesn't matter if they're submitting to the NEJM or other publisher, the NEJM embargo policy should be essentially the same as any of the others and a protocol which should be followed in general until a product has been peer reviewed. I'm not aware of Abstracts being revealed for any of the presentations made to date, the conferences were certainly attended by peers of the presenters, but without an Abstract which is reviewed and accepted by peers I'm not certain they meet the full peer review requirements.
It should be noted that an Abstract for Dr. Liau's appearance at SNO should be released on November 11th, as I remember it. I believe it would be completely proper for the Journal to be released between the 11th and Dr. Liau's presentation and for her to discuss what's in the Journal with all attending. I can't say this will happen, just that I believe it's possible.
Gary