Cancer of Unknown Primary (CUP) represents a heterogeneous group of metastatic tumours for which the site of origin is not identified at the time of diagnosis after a standardized diagnostic work up. CUP accounts for 3-5% of malignancies and generally the prognosis is poor for patients treated with generic platinum-based chemotherapy to cover a range of possible diagnoses. Accurate identification of the primary tumor in CUP cases can allow more specific treatment selection and hence improve patient outcomes. In addition, molecular profiling may identify a range of mutations that could be targets for treatment.
Patients with CUP may not be well managed in a tumour-stream based cancer centre. Hence we set up a dedicated CUP clinic at PeterMac in 2012. Patients undergo appropriate diagnostic work-up as per CUP ESMO guidelines. PET/CT is performed in selected cases. In addition, as part of a Cancer Australia and NHMRC funded cohort study, patients’ tumours undergo profiling for actionable mutations and assessment with the CUPGuideTM tissue of origin assay. The study is now open in multiple other sites and states to improve access for patients. In a recent review of PeterMac CUP clinic patients we found that more than half of patients attending the clinic had their primary site identified. In addition, the results of PET/CT and CUPGuide commonly impacted on patient management. Challenges include working with limited tissue from small biopsy specimens and managing patient distress. Examples of mutation profiling results and use in practice will be presented. In conclusion, having a dedicated clinic and research effort to focus on CUP patients can improve outcomes for these previously neglected group of patients.