30 Background: Cancer pain prevalence is high (52%-77%) with breakthrough pain flares and end-of-dose failure adding to patient suffering and increased health care utilization. Shared decision-making (SDM), incorporating patient-stated preferences, goals, and concerns, can foster comprehensive pain assessment (CPA) and improve pain outcomes. Methods: This study will evaluate SDM and CPA in patients with cancer to manage chronic and breakthrough pain. Eligible patients have pain or are taking opioids to manage chronic cancer pain. Patients complete a tablet-based survey at enrollment to record baseline pain and activity levels, pain flare severity and length, end-of-dose pain, and SDM preferences. Results are presented on an electronic dashboard and the provider and patient collaboratively establish a pain care plan. The effectiveness of SDM on pain outcomes will be measured with the Pain Care Quality Survey. Results: Pain characterization is described for the first 43 patients enrolled, of which 42% (n=18) desire to share decision-making with the provider, while 35% (n=15) prefer to make the final decision after considering provider input. Patients are 57% (n=26) female with a mean age of 56 (range 20-93); baseline mean pain scores were 5.4, and overall distress scores were 5.43, (scale 0-10); 91% had a pain flare in the last seven days with mean severity of 5.53; 72% of flares lasted longer than 30 minutes. All patients had end-of-dose pain. Less than half (42%) have restricted activity and 23% manage self-care but cannot work. Participants reported incident pain associated with certain activity (63%) as well as insidious pain not associated with activity (65%). Enrolled patients selected 143 pain descriptors: burning (16), achy (24), sharp and stabbing (21), pins and needles (15), cramping (14) radiating (14), intermittent (19), and continuous (20). Conclusions: The majority (77%) of patients desire SDM. Although most patients were already taking opioids at presentation, they had moderate pain and distress, frequent flares and end of dose pain, and limitations on activity level due to the pain. Baseline pain characterization with a drill down CPA offers opportunity to use SDM to develop effective pain care plans and measure outcomes. Clinical trial information: NCT03304145.