This document provides an overview and analysis of Twitter coverage of the 2015 American Society of Clinical Oncology (ASCO) annual meeting. It includes statistics on the total number of tweets during the meeting and breakdowns of the tweets by day and topic. The top tumor types discussed were lung cancer, breast cancer, and melanoma. Key clinical studies for each of these cancers are also highlighted and the sentiment of healthcare professionals around these studies is analyzed. Influential healthcare professionals on Twitter for each topic are also identified.