Tumors of unknown origin are actually metastases of unknown origin. These tumors are referred to as metastatic tumors, excluding malignant hemopathies and lymphomas. The origin of the tumors is not detected by a detailed medical history (chest X-ray, blood and urine analysis and adequate histological evaluation).
Examinations of these patients for primary tumor screening are excessive and pointless in most cases. The primary tumor is found in only 15% of cases, and finding the primary tumor does not affect prognosis or treatment. They are advanced tumors that can rarely be cured and do not respond to palliative chemotherapy. Only 20% of these tumors respond to treatment.
Cancer Symptoms and Diagnostic Tests
About 6% of cancer patients present as a metastasis of unknown origin.
The most frequent symptoms are pain, masses in the liver, lymph nodes or pathological ganglia, bone pain or pathological fractures, respiratory symptoms, disorders of the nervous system, weight loss or skin nodules.
Always perform a more accessible ganglion or tumor biopsy. The pathologist must perform an examination of the piece with special techniques that can guide the origin of the tumor. These examinations must be performed before radiographic examinations, since the findings of the pathologist can guide the search for the primary tumor.
There are some particular locations such as pathological ganglia in the neck that guide the primitive tumor to be larynx or pharynx and treat them as if the primitive tumor was the one cited even if the otolaryngologist does not see it.
The same happens in the case of malignant nodes in the armpit, which are treated in a woman as if the origin were mammary although no tumor is detected in the breast. In this case the origin could also be the lung.
Cancer findings of unknown origin
These tumors are poorly prognosed and treatment with chemotherapy rarely manages to heal them, especially when it comes to undifferentiated tumors. In cases where the primary tumor is found, the treatment is the tumor itself, considering that it is already an advanced or metastatic tumor. Good histological analysis is essential, using appropriate techniques including molecular biology analysis and close oncologist-pathologist collaboration. Finally, doing many radiographic, endoscopic and analytical examinations is not the most appropriate and also does not improve the prognosis. These tumors are treated with chemotherapy and the response rate is less than 30%.