[DIAGNOSTICS AND TREATMENT OF MALIGNANT TUMOURS WITHOUT DETECTED PRIMARY SITE]

Tumours without detected primary site (CUP syndrome) make up a heterogenous group of malignant neoplasms in which symptoms of metastatic process appear earlier than symptoms ofprimary tumour that is impossible to identify by the existing methods. The number of patients with CUP syndrome remains practically unaltered (3-5% of all oncological patients, according to WHO statistics) despite marked extension of the range of modern instrumental and radiodiagnostic methods. Unique biological nature of these tumours awaits elucidation. The available data suggest that dissemination ofthe process may occur in the absence ofprimary tumour growth due to hereditary aggressiveness of cancer cells or alteration of their properties after penetration into a target organ. Comprehensive examination of patients with CUP syndromefor the search of the primary site must include a series of physical, instrumental, radiodiagnostic, laboratory and morphological studies on a simple-to-complex basis. The treatment of CUP syndrome must take into consideration the extent of the lesion and the necessity of morphological verification of metastases. Anti-tumour therapy should be started immediately after establishment of diagnosis while continuing the search for the primary site. Once the primary tumour is detected, the primary site and metastases must be treated simultaneously in order to improve the long-term results of therapy.