PURPOSE: Research eliciting patients' illness concerns has typically focused later in the cancer continuum, rather than during cancer treatments. Family caregiver concerns are overlooked during this time. Less is known about how patients and caregivers prioritize concerns during cancer treatments, which holds potential for improving supportive oncology care (ie, primary palliative care). The purpose of this study was to elicit and compare which domains of supportive oncology are of highest importance to patients and caregivers during cancer treatments. METHODS: Freelisting, a cognitive anthropology method, was used to elicit concerns in order of importance. Freelist data were analyzed using Smith's salience index. Qualitative interviews were conducted with a caregiver subsample to add explanatory insights. RESULTS: In descending order, pain, death, fear, family, and awful were salient Freelist items for patients (n = 65), whereas sadness, time-consuming, support, anger, tired, death, and frustration were salient for caregivers (n = 24). When integrated with supportive oncology domains, patients' concerns reflected a prioritization of the physical (pain) and emotional (death, fear, and awful) domains, with less emphasis on social (family) aspects. Caregivers' prioritized the emotional (sadness, anger, death, and frustration) and social (time-consuming and support) domains, with less emphasis on the physical (tired) aspects. CONCLUSION: Our findings suggest that enhancing primary palliative care delivery by oncology teams requires systems thinking to support both the patient and caregiver as the primary unit of care. Primary palliative care may be improved by prioritizing interventions that address physical concerns among patients as well as key social concerns among caregivers to support the complex caregiving role while patients undergo cancer treatments.