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

Abstract

BackgroundUp 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.MethodsWe 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.ResultsOf 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.ConclusionIdentification 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.

Operative and peri‐operative considerations in the management of brain metastasis

“…In 10%-25% of cases, intracranial metastases are the only detectable evidence of a systemic primary cancer at diagnosis; for these patients, intracranial tumor sampling may offer the only means for obtaining a histologic diagnosis ( Figure 3), and is thus essential for guiding further treatment. [12][13][14] Patients experiencing significant neurological symptoms (such as impairments in cognition or speech, motor weakness or neglect, or seizures) attributable to mass effect, edema, or hydrocephalus benefit from resection as a means of rapid symptom resolution; it may additionally enable reduction or discontinuation of adjunct therapies such as steroids. For tumors in eloquent or difficult-to-access locations in the brain, whereas open resection may put the patient at high risk for postoperative neurological deficits or complications, a stereotactic biopsy may be a safer approach.…”

“…Surgery offers a number of distinct advantages over other types of therapy for BM. In 10%‐25% of cases, intracranial metastases are the only detectable evidence of a systemic primary cancer at diagnosis; for these patients, intracranial tumor sampling may offer the only means for obtaining a histologic diagnosis (Figure ), and is thus essential for guiding further treatment . Patients experiencing significant neurological symptoms (such as impairments in cognition or speech, motor weakness or neglect, or seizures) attributable to mass effect, edema, or hydrocephalus benefit from resection as a means of rapid symptom resolution; it may additionally enable reduction or discontinuation of adjunct therapies such as steroids.…”

Pineal Gland Metastasis From Poorly Differentiated Carcinoma of Unknown Primary Origin

“…In our case, radiosurgery was offered for adjuvant treatment of the two intracranial lesions despite the lack of identification of a primary lesion. Han et al retrospectively evaluated 540 patients who underwent gamma knife radiosurgery and demonstrated that identification of a primary tumor prior to the initiation of gamma knife radiosurgery did not affect patient outcomes (6). This emphasizes that radiosurgery can be an effective adjuvant treatment modality for brain metastases in cases without a primary lesion.…”

“…Carcinoma of unknown primary origin (CUP) is a heterogeneous group of cancers defined by the presence of metastatic disease without an identifiable primary tumor on metastatic workup (5,6). CUP has been reported to constitute 2-5% of all cancer cases and, remarkably, represents up to 15% of all patients with brain metastases (5,6). Here, we present a case of a 65-year-old male found to have a heterogeneously enhancing lesion of the pineal gland as well as an enhancing lesion of the left cerebellar hemisphere.…”

Survival outcomes following craniotomy for intracranial metastases from an unknown primary

“…Patients with cancer of an unknown primary (CUP) comprise approximately 5–15% of total cerebral metastases cases [ 8 , 22 , 24 , 26 , 33 ]. Patients presenting with intracranial metastases from a CUP may not be considered for the same surgical treatment options as those afforded to patients with a known primary cancer (CKP) as knowledge of the primary disease’s prognosis typically facilitates treatment decisions [ 2 ].…”