Introduction: Many physicians seek information from colleagues over other sources, highlighting the important role of interaction in continuing professional development (CPD). To guide the development of CPD opportunities, this study explored the nature of cancer-related questions faced by general surgeons, and how interaction with colleagues addressed those questions. Methods: This study involved thematic analysis of field notes collected through observation and transcripts of telephone interviews with 20 surgeons, two pathologists, one medical oncologist, and one radiation oncologist affiliated with six community hospitals participating in multidisciplinary cancer conferences by videoconference in one region of Ontario, Canada. Results: Six multidisciplinary cancer conferences (MCCs) were observed between April and September 2006, and 11 interviews were conducted between December 2006 and January 2007. Sharing of clinical experience made possible collective decision making for complex cancer cases. Physicians thought that collegial interaction improved awareness of current evidence, patient satisfaction with treatment plans, appropriate care delivery, and continuity. By comparing proposed treatment with that of the group and gaining exposure to decision making for more cases than they would see in their own practices, physicians developed clinical expertise that could be applied to future cases. Little collegial interaction occurred outside these organized sessions. Discussion: These findings highlight the role of formally coordinated collegial interaction as an important means of CPD for general surgeons. Investment may be required for infrastructure to support such efforts and for release of health professional time for participation. Further research is required to examine direct and indirect outcomes of collegial interaction. (Contains 1 figure and 1 table.)