Patterns of distant metastases in nasopharyngeal carcinoma

The distant metastasis in nasopharyngeal carcinoma has remained the major cause of mortality and treatment failure despite better locoregional control of the disease in the past decades. Between 1987 and 1992, 125 out of 629 cases of nasopharyngeal carcinoma were found to have distant metastasis. The location of metastatic site, the timing and median survival were analyzed. The diagnosis of distant metastasis in the retrospective study was based on radiography, computed tomography, skeletal scintigraphy, abdominal sonography and pathology reports. The results showed that the frequencies of metastases were as follows: bone (75% of total metastatic patients), lung (46%), liver (38%), retroperitoneal lymph nodes (10%). Multiple organ involvement was high (57%). Most of the distant metastases (95%) occurred within 3 years after completion of radiotherapy, the first year (52%), the second year (23%) and the third year (20%). The median survival time from the discovery of distant metastasis was 11.2 months for bone metastasis, 16.3 months for pulmonary metastasis, and 3.2 months for hepatic metastasis. The results revealed that the skeletal system was the most common site of distant metastasis, followed by lung and liver. The incidence of retroperitoneal lymphadenopathy is higher than previous reports.