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The clinical presentation and favorable prognosis of patients with isolated metachronous brain metastasis from germ cell tumors.

OBJECTIVE
We conducted the present study to elucidate the clinical presentation, treatment outcomes and risk factors for the development of metachronous brain metastasis at a single progressive disease site, the so-called isolated brain metastasis, in patients with testicular germ cell tumors.


METHODS
To identify metachronous brain metastasis in a timely manner, brain imaging was performed when the re-elevation of tumor markers was observed during chemotherapy, even in patients who were free from central nervous system symptoms. The medical records of 147 patients with metastatic germ cell tumors who were treated between 1991 and 2015 were retrospectively reviewed.


RESULTS
Eight (5.4%) of the 147 patients presented synchronous brain metastasis. Of these, five patients suffered from metachronous brain metastasis relapse. An additional nine patients developed metachronous brain metastasis during or after chemotherapy. Ten of the 14 patients with metachronous brain metastasis did not have central nervous system symptoms. Eight (57%) patients had isolated brain metastasis. Ten patients underwent multimodal treatments, predominantly chemotherapy and radiotherapy. The 3-year overall survival of all 14 patients was 34.6%, but that of the patients with isolated brain metastasis was high as 66.7%. The development of metachronous brain metastasis was associated with a choriocarcinoma element at the primary site and an human chorionic gonadotropin level of >50 000 IU/L and brain metastasis at the initial diagnosis.


CONCLUSIONS
In our series, we identified isolated brain metastasis in 57% of the metachronous brain metastasis patients. The monitoring of tumor markers and appropriate brain imaging are mandatory for the diagnosis of isolated brain relapse, which is associated with a higher rate of long-term survival.