Aims:
Carcinomas of unknown primary sites (CUP) are metastatic malignancies in which a primary tumour cannot be identified despite extensive workup. They are associated with poor prognosis and impaired quality of life. A dedicated CUP clinic was established at our centre to facilitate investigations and provide access to molecular analysis. This audit evaluates the clinic’s experience.
Methods:
After gaining ethics approval, a retrospective medical record review was conducted for patients seen in the CUP clinic from 01/07/2014 to 3/8/2020. Patient demographics and clinicopathological details were extracted.
Results:
A total of 463 patients were booked to the CUP clinic. Of these, 102 with clear non-CUP pathology were excluded, leaving 361 patients for review. Median age was 62 years and 53% were female. A diagnosis of CUP was established in 167 of 361 (46%) patients and malignancy other than CUP in 153 patients (42%). Molecular analysis was requested in 131/167 (78%) patients with CUP and changed management in 31%. After investigation, 86/167 (51%) CUP patients received ongoing care at our centre. Of these, patients who underwent molecular analysis had longer overall survival (OS) than those who did not (median OS 18.3m vs 9.9m, HR 0.45, p=0.0031, 95% CI 0.22-0.92). Systemic therapy was used in 67% of patients. Site- or molecular-directed therapy was associated with improved OS compared to empirical chemotherapy (median OS 21.3 vs 10.1 months, HR 0.46, p=0.0028, 95% CI 0.25-0.85) Favourable subtypes of CUP had improved OS compared to non-favourable subtypes (median OS 64.4m vs 12.2m, HR 0.35, 95% CI 0.20-0.60, p=0.0014).
Conclusions:
A dedicated CUP clinic has helped to confirm a specific non-CUP diagnosis and direct management in half of patients. Molecular analysis was ordered frequently and changed management in a third of patients with CUP. Improved overall survival was associated with favourable subtypes and treatment with site-directed therapies.