Cancer of unknown primary: Diagnosis, treatment and technological advances

Cancer of unknown primary (CUP) is a clinical type of metastatic malignancy where the primary tumor remains unidentified despite thorough diagnostic evaluation. It presents a significant challenge in modern oncology due to its complex management and diagnostic difficulties. Although CUP accounts for approximately 2 to 5% of cancer cases worldwide, recent advancements in diagnostic techniques, such as immunohistochemistry and genomic sequencing, have improved the ability to classify and treat CUP using targeted therapies. However, limitations persist, including the biological heterogeneity of CUP and the frequent need for empirical treatments. This review discusses advancements in CUP diagnosis and treatment, emphasizing the importance of a multidisciplinary approach that integrates precision oncology and palliative care to enhance patient quality of life.