Trial Comparing Cisplatin With or Without Gemcitabine in Patients With Carcinoma of Unknown Primary

Inclusion Criteria: Patients older than 18 years Evidence of CUP based on histologic examination Negative search for the primary tumor site using recommended guidelines Disease classified as good prognosis according to the French classification criteria: *performance status >2 and *normal serum LDH No prior chemotherapy No previous carcinoma, except basal-cell carcinoma of the skin Adequate renal function: measured or calculated creatinine clearance > 60 ml/min Absolute granulocyte count ≥ 1,500/mm3; platelets ≥ 100,000 mm3; bilirubin ≤ 1.5 fold the upper normal value Signed informed consent Exclusion Criteria: Patients infected by the Human Immunodeficiency Virus (HIV) CUP belonging to one of the following subgroups: 1) Axillary lymph node of an adenocarcinoma in a woman; 2) Serous adenocarcinoma of the peritoneum in a woman; 3) Undifferentiated carcinoma of the middle line in a young man; 4)Squamous-cell carcinoma; 5) Neuroendocrine carcinoma; 6) Bone metastases with elevated serum prostate specific antigen (PSA) in a man Patients who do not fit inclusion criteria.