Background: Cancer of unknown primary site (CUP) comprises a relatively frequently occurring group of heterogeneous malignant tumors in the clinical routine, which currently has an abysmal prognosis for affected patients. Based on the improved diagnostic tools it is now possible to identify subgroups of patients with different clinical prognoses. New therapies adapted to these identified subgroups are becoming increasingly more relevant.
Aim: This review aims to evaluate the role of surgery and different surgical options in the therapy of patients with CUP.
Results: For the treatment of patients with CUP it is important to identify subgroups of patients with a better prognosis. Surgical resection of CUP metastasis is a therapy option leading to a prolonged survival in (1) women with papillary peritoneal adenocarcinomatosis, (2) women with axillary lymph node metastasis of adenocarcinoma, (3) patients with cervical lymph node metastasis of squamous cell carcinoma, (4) patients with inguinal lymph node metastasis, (5) patients with poorly differentiated carcinomas with midline distribution (e.g. extragonadal germ cell syndrome) and (6) patients with small resectable tumors.
Conclusion: Surgery is an important therapy option in different subgroups of patients with CUP. Together with multimodal therapy, adjusted according to the identified most likely origin of the primary tumor, it is possible to prolong patient survival.