Health service utilisation and risk factors for cancer of unknown primary (CUP).

Cancer of unknown primary (CUP) is a diagnosis used to describe patients with metastatic cancer with no identifiable primary site of origin at the time of presentation. CUP is the fourth most common cause of cancer death in NSW, but little is known about its risk factors or management. We will examine the patterns of health care utilisation prior to and after a CUP diagnosis in a cohort of Department of Veterans’ Affairs clients residing in NSW and in the 45 and Up Study cohort using linked cancer registry, hospital admission, emergency department, mortality and pharmaceutical and medical service claims. We will also undertake a nested case-control study to explore the risk factors for CUP, utilising baseline 45 and Up Study data and administrative health data prior to diagnosis.