The 2015 AACR (American Association for Cancer Research) Annual Meeting and Exhibition, held April 18–22 at the Pennsylvania Convention Center in Philadelphia, highlighted the latest, most exciting discoveries in every area of cancer research.

The annual meeting attracted a record-breaking 19,250 attendees, which was up 4 percent from last year’s meeting held in San Diego.

While Philadelphia is more convenient to those traveling from Europe and is situated midway between New York and Washington D.C., Pam Ballinger, senior director of meetings and exhibits at the AACR, felt convenience was not the driving factor in attendance.

“I think it’s scientific content more than anything else. The content presented here is very hot and very new. With the clinical trials being presented, this is big,” Ballinger said. “I suspect we’ll do as well, or break another record in New Orleans next year.”

With vast amounts of cancer research taking place all over the world in more than 200 different types of cancer, it would be impossible to include it all during a five-day meeting.

In order to fit as much as possible into the program, sessions began at 7 A.M. every day and ended at 6:30 P.M. One very hot topic of the week was immunotherapy and attendees packed those sessions full to over flowing.

Researchers presented 6000 posters in the exhibit hall during the meeting. Poster sessions were given a prominent location in the exhibit hall with the primary intent to drive traffic to that area. The posters also help to drive networking and interaction between attendees, as well as the exchange of scientific information.

Ballinger reported that, according to exhibitors, of which there were 435 covering 85,000 net square feet of exhibit space, the traffic in the exhibit hall was the highest it has ever been. AACR not only sold out their exhibit space, but also had a waiting list.

Even those who were not able to attend the annual meeting were able to get in on the action via an hour-long ABC News Twitter chat that was streamed live on Periscope.

ABC News Medical Editor Richard Besser, MD, moderated the chat and was joined by AACR representatives, researchers and other attendees.

While AACR had hosted Tweet chats with ABC News before, the addition of the live stream was a new experiment. The live stream allowed for a meatier dialog amongst the panelists and the Twitter audience.

The topic of clinical trials generated quite a bit of discussion amongst the panelists, as well as those tuning in on Twitter. The entire event was captured and streamed via an iPad and occurred  without any problems.

Next year’s annual meeting will take place April 16-20 in New Orleans.