Healthcare Costs Before and After Diagnosis of Cancer of Unknown Primary Versus Ovarian Cancer in Australia

BACKGROUND: Little is known about the healthcare resource usage and costs for patients with cancer of unknown primary (CUP). OBJECTIVE: The aim of this study was to describe and quantify healthcare resource use and costs in Australia, 6 months prior to and after a diagnosis of CUP, and compare to those of women with ovarian cancer. METHODS: Individual-level data combining baseline surveys, clinical records and Medicare Benefits Schedule (MBS) claim records were analysed for 149 patients with CUP and 480 patients with ovarian cancer from two prospective cohort studies. MBS data were aggregated for the period 6 months prior to diagnosis date and 6 months after diagnosis. Data included doctor consultations, pathology, diagnostics, therapeutic procedures, imaging, allied health and medicines. Generalised linear models were used to evaluate the cost differences between CUP and ovarian cancer using gamma family and log link functions. Models were adjusted for age, employment, marital status, surgery, chemotherapy and number of comorbidities. RESULTS: The mean healthcare costs in the 6 months prior to diagnosis of CUP were Australian (AU) $3903 versus AU$1327 for ovarian cancer (adjusted cost ratio 2.94, 95% confidence interval [CI] 2.08–4.15). Mean healthcare costs 6 months post-diagnosis were higher for patients with CUP versus ovarian cancer (AU$20,339 vs AU$13,819, adjusted cost ratio 1.47, 95% CI 1.13–1.92). Higher costs for patients with CUP were driven by imaging (AU$1937 vs AU$1387), procedures (AU$5403 vs AU$2702) and prescribed medicines for all conditions (AU$10,111 vs AU$6717). CONCLUSIONS: Pre-diagnosis costs for patients with CUP are nearly triple those for ovarian cancer. Six months after diagnosis, healthcare costs for CUP remained higher than for ovarian cancer due to imaging, procedures and medicines. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s41669-022-00371-1.