Brain Tumor Res Treat.  2016 Oct;4(2):107-110. 10.14791/btrt.2016.4.2.107.

Optimal Treatment Decision for Brain Metastases of Unknown Primary Origin: The Role and Timing of Radiosurgery

• Han HJ
• Chang WS
• Jung HH
• Park YG
• Kim HY
• Chang JH

• KMID: 2356978
• DOI: http://doi.org/10.14791/btrt.2016.4.2.107

Abstract

BACKGROUND
Up to 15% of all patients with brain metastases have no clearly detected primary site despite intensive evaluation, and this incidence has decreased with the use of improved imaging technology. Radiosurgery has been evaluated as one of the treatment modality for patients with limited brain metastases. In this study, we evaluated the effectiveness of radiosurgery for brain metastases from unknown primary tumors.
METHODS
We retrospectively evaluated 540 patients who underwent gamma knife radiosurgery (GKRS) for brain metastases radiologically diagnosed between August 1992 and September 2007 in our institution. First, the brain metastases were grouped into metachronous, synchronous, and precocious presentations according to the timing of diagnosis of the brain metastases. Then, synchronous and precocious brain metastases were further grouped into 1) unknown primary; 2) delayed known primary; and 3) synchronous metastases according to the timing of diagnosis of the primary origin. We analyzed the survival time and time to new brain metastasis in each group.
RESULTS
Of the 540 patients, 29 (5.4%) presented precocious or synchronous metastases (34 GKRS procedures for 174 lesions). The primary tumor was not found even after intensive and repeated systemic evaluation in 10 patients (unknown primary, 34.5%); found after 8 months in 3 patients (delayed known primary, 1.2%); and diagnosed at the same time as the brain metastases in 16 patients (synchronous metastasis, 55.2%). No statistically significant differences in survival time and time to new brain metastasis were found among the three groups.
CONCLUSION
Identification of a primary tumor before GKRS did not affect the patient outcomes. If other possible differential diagnoses were completely excluded, early GKRS can be an effective treatment option for brain metastases from unknown primary tumor.

Keyword

Neoplasm metastasis; Neoplasms, Unknown primary; Radiosurgery

MeSH Terms

Brain*
Diagnosis
Diagnosis, Differential
Humans
Incidence
Neoplasm Metastasis*
Neoplasms, Unknown Primary
Radiosurgery*
Retrospective Studies

Figure

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  Fig. 1 Kaplan-Meier curve of survival time showing no statistically significant difference in median survival time after gamma knife radiosurgery among the groups (p>0.05). Cum survival, cumulative survival; Survival time, survival time in months; Unknown, unknown primary group; Delayed, delayed known primary group; Synch, synchronous metastasis group.

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  Fig. 2 Kaplan-Meier curve of the time to new brain metastases showing no statistically significant difference in median time to new brain metastases among the group (p>0.05). Cum survival, cumulative survival; Survival time, survival time in months; Unknown, unknown primary group; Delayed, delayed known primary group; Synch, synchronous metastases group.

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