PURPOSE: We sought to characterize patient-oncologist communication and decision making about continuing or limiting systemic therapy in encounters after an initial consultation, with a particular focus on whether and how oncologists foster shared decision making (SDM). METHODS: We performed content analysis of outpatient oncology encounters at two US National Cancer Institute–designated cancer centers audio recorded between November 2010 and September 2014. A multidisciplinary team used a hybrid approach of inductive and deductive coding and theme development. We used a combination of random and purposive sampling. We restricted quantitative frequency counts to the coded random sample but included all sampled encounters in qualitative thematic analysis. RESULTS: Among 31 randomly sampled dyads with three encounters each, systemic therapy decision making was discussed in 90% (84 of 93) encounters. Thirty-four (37%) broached limiting therapy, which 27 (79%) framed as temporary, nine (26%) as completion of a standard regimen, and five (15%) as permanent discontinuation. Thematic analysis of these 93 encounters, plus five encounters purposively sampled for permanent discontinuation, found that (1) patients and oncologists framed continuing therapy as the default, (2) deficiencies in the SDM process (facilitating choice awareness, discussing options, and incorporating patient preferences) contributed to this default, and (3) oncologists use persuasion rather than deliberation when broaching discontinuation. CONCLUSION: In this study of outpatient encounters between patients with advanced cancer and their oncologists, when discussing systemic therapy, there exists a default to continue systemic therapy, and deficiencies in SDM contribute to this default.