[Cervical lymph node metastasis from an unknown primary tumor]

Between June/1986 and June/1999, we treated 18 cases of previously untreated metastatic carcinoma in cervical lymph nodes from an unknown primary tumor. Among them, 15 cases were squamous cell carcinoma, 2 were adenocarcinoma, and one was undifferentiated carcinoma. The dose of radiotherapy, which was planned only for the cervical lymph nodes, was 60-70 Gy at the metastatic sites. Preventive radiotherapy at possible primary sites was performed only in one case. After these treatments, a primary lesion appeared in only two cases: in one case a tumor was found in the hypopharynx, and the other, which had been diagnosed as undifferentiated carcinoma, proved to be malignant lymphoma. Outcomes were analyzed except for these two cases. The five-year survival rate was 31%. The loco-regional control rate was 57% after radiation treatment limited to the affected cervical lymph nodes. Distant metastasis appeared more often in open-biopsy cases than in those receiving fine-needle aspirations (FNA). According to these results, treatment of possible primary sites may not be necessary, and for initial pathological diagnosis, FNA is recommended, while open biopsy should be avoided, if possible.