Distant metastasis in patients with myxofibrosarcoma.

PURPOSE: A clinical feature of myxofibrosarcoma is local recurrence, but knowledge about distant metastasis is sparse. We evaluated the tendency of clinical and histological features of metastasis in myxofibrosarcoma patients.

METHODS: Fifty-eight patients with myxofibrosarcoma were treated in our hospitals, and a total of 16 consecutive patients with distant metastases were included in this retrospective study (9 males and 7 females, with a mean age of 77 years). Because there was no patient complicated by both lung and lymph node metastases, we compared the age, sex, tumor size and location, French Federation of Cancer Centers Sarcoma Group (FNCLCC) grade, American Joint Committee on Cancer (AJCC) stage, and times of the first metastasis from the initial examination between the lung and lymph node groups. In addition, we examined factors affecting the prognosis.

RESULTS: The median follow-up period was 42.9 months (range 8-142). Eleven of 16 patients developed pulmonary metastases. The sites of extra pulmonary metastases were the lymph nodes in 5 patients, bone in 1, subcutaneous in 1, intramuscular in 1, and peritoneum in 1. The median time for patients to develop distant metastases was 17.4 months (range 0-59). The time until the onset of the first metastasis in the lung metastasis group was significantly shorter than in the lymph node group (p < 0.05). Also, the survival rate in the lymph node metastasis group was better than in the lung metastasis group (p < 0.05).

CONCLUSIONS: Not only lung metastasis but also lymph node metastasis occurs frequently in myxofibrosarcoma patients. Myxofibrosarcoma with lung metastasis is more aggressive than the type with lymph node metastasis.