Nationwide survey on family caregiver-perceived experiences of patients with cancer of unknown primary site

Cancer of unknown primary site (CUP) is an aggressive disease with poor prognosis. As research on the experiences of CUP patients and their families is scarce, this study aimed to compare the family caregiver-perceived burden of CUP with that of common cancers (lung, colon, and stomach cancers). The association between family caregiver-perceived burden and CUP patients' quality of life (QOL) at end-of-life and family depression, respectively, was also explored.This was a pre-planned secondary analysis of nationwide cross-sectional survey data from the bereaved family caregivers of patients with cancer who died at 286 institutions. The major measurements were the eight-item family caregiver-perceived Burden scale (comprising specialist access, uncertainty, and prolonged diagnosis), Good Death Inventory, and Patient Health Questionnaire 9.Of 27,591 survey responses, we analyzed 97 and 717 responses from family caregivers of patients with CUP and common cancer, respectively. The families of CUP patients scored significantly higher on all three burden subscales than those of common cancer patients (effect sizes: specialist access subscale, 0.3; uncertainty subscale, 0.66; and prolonged diagnosis subscale, 0.69; adjusted P 0.01). Greater family burden was significantly associated with lower patient QOL and higher family depression. Burden was significantly associated with being a spouse, second opinion consultation, and diagnosis period of 1 month.The family caregivers of CUP patients experience poor specialist access, greater uncertainty, and a prolonged diagnosis. They should be cared for from the initial stages to establish access to specialists, obtain an early diagnosis, and reduce uncertainty.