A patient is someone who has ever been diagnosed with cancer.
A caregiver, in this instance, is a family caregiver or informal caregiver (i.e., a relative or friend) who provides physical, emotional, financial, spiritual, or logistical (e.g., transportation, errands) support to someone diagnosed with cancer. Caregivers often provide help with everyday tasks, including medical appointments, assistance with bills and insurance claims, and household and other daily responsibilities.