Muhannad Alzamzami, Tara M. Connelly, Abeera Mehmood, Muhammad Shoaib Khan, Gerry O’Donoghue
Background: Cancer of unknown origin (CUO) is a distressing diagnosis for patients. We aimed to determine the number and clinical course of patients diagnosed with CUO investigated in the Southeast of Ireland from 2008–2016.
Methods: Gastrointestinal multidisciplinary meeting (MDM) records were queried from 09/2008–09/2016 to identify patients discussed for CUO. NIMIS and lab enquiry systems were used to record the radiological investigations (number and type), biopsies (modality and histopathological result), tumour markers (number and type) and definitive diagnosis (CUO vs. primary discovered during investigation).
Results: Eighty-seven patients [mean age 68.9±15.6, 43 (49%) male] were discussed at MDM with an initial diagnosis of CUO during the study period. A primary aetiology was ultimately determined for 36 (41.3%) of patients. The majority were hepatobiliary (n=12), followed by colorectal (n=5), genitourinary (n=2), upper gastrointestinal (n=3), lung (n=2), other cancer (n=7) and non-malignant aetiologies (n=5). Fifty-one patients [mean age 65±11.4, 26 (50.9%) male] maintained a diagnosis of CUO. The majority presented in 2013 (n=13). The majority presented with abdominal pain (n=20), weight loss/malaise (n=10), incidental finding (n=11) or other (n=10). This cohort underwent 547 radiological investigations, 69 biopsies, 44 endoscopies and 19 surgeries. Forty-six (90.1%) had a biopsy, the gold standard for the diagnosis of malignancy.
Conclusions: Despite multiple radiological, endoscopic investigations and biopsies, in approximately 60% of patients presenting with CUO, a primary was not found. Abdominal pain was the most common presenting symptom. When a primary was discovered, the majority were hepatobiliary in origin.
