Established Serum Biomarkers Are Prognostic Factors in Patients With Oligometastatic Cancer and Brain Involvement

This study was designed to evaluate the prognostic impact of the previously validated LabBM score (serum lactate dehydrogenase, C-reactive protein, albumin, hemoglobin, platelets) in a new setting, namely patients with a limited number of brain metastases, arbitrarily defined as max. 4 brain lesions, from common tumor types such as lung and breast cancer. A total of 5 metastatic lesions overall were allowed to comply with current definitions of oligometastatic cancer. For this retrospective single-institution analysis, 101 patients were identified from a previously described, prospectively maintained database. Twenty-one patients (21%) had extracranial metastases. Non-small cell and small cell lung cancer were the prevailing tumor types (78%). Forty-nine patients (49%) had normal blood test results (LabBM score 0 points). Their median survival (23 months) was significantly longer than that of patients with higher LabBM score. In multivariate analysis, LabBM score, performance status and single brain metastasis were associated with significantly better survival. Limited extracranial metastases did not impair prognosis. Patients with LabBM score 0 had a 5-year survival rate of 27% after surgery (n=24) and 39% after stereotactic radiotherapy (n=13), respectively (p=0.3). Blood biomarkers can be regarded as surrogate of the metastatic burden in the body, which is not always detectable by imaging methods. In contrast to circulating tumor cells and other emerging markers, the LabBM score is inexpensive. Patients with LabBM score >0 had a 2.8-fold increased risk of death. The score might be helpful in predicting survival improvement provided by ablative local treatment of oligometastases.