Factors Associated with Survival in Patients with Intracranial Metastases

Introduction: Brain metastases are a devastating complication of cancer with an incidence tenfold that of primary malignant brain tumors.

Methods: Patients who underwent a craniotomy for resection of an intracranial metastasis between 2009-2024 were identified by searching for CPT and ICD codes. Retrospective data were obtained from electronic medical records. Survival was calculated from time of primary cancer diagnosis. Associations between categorical and linear variables were analyzed using Kruskal-Wallis tests, and associations between linear variables were analyzed using linear regression.

Results: Data were reviewed for 294 patients. Primary cancers were categorized as follows: lung (n=85), breast (n=62), melanoma (n=44), genitourinary (n=27), gastrointestinal (n=25), gynecologic (n=14), unknown (n=2), and other (n=35). Primary cancer category was associated with overall survival (p < 0.001) and number of brain metastases (BM) upon initial detection (p=0.041). Melanoma presented with the greatest number of BM upon initial detection (median=2,IQR=3). Lung cancer was associated with the shortest median survival time (759 days,IQR=790), followed by genitourinary (852 days,IQR=1516), gynecologic (1161 days,IQR=261), gastrointestinal (1880 days,IQR=1070), melanoma (2273 days,IQR=2544), then breast (2531 days,IQR=2213).

Factors associated with improved survival included increased time from diagnosis of primary cancer to brain metastasis(p < 0.001) and history of radiation for brain metastases(p=0.031). Meanwhile, factors associated with decreased overall survival included increased age at primary cancer diagnosis(p < 0.001), single relationship status(p=0.008), and history of tobacco use(p=0.021). Incidence of leptomeningeal enhancement was associated with an increased number of total brain metastases(p=0.013), male sex(p=0.016) and history of tobacco use(p=0.033). The number of new brain metastases developed after initial detection was associated with increased time from diagnosis to first craniotomy for tumor resection, increased maximal midline shift(p=0.008), and increased incidence of leptomeningeal enhancement(p=0.008).

Conclusion : Lung cancer was associated with the shortest median survival time. Increased time between diagnosis of intracranial metastases and first craniotomy for tumor resection was associated with the development of an increased number of brain metastases. Radiation for intracranial metastases was associated with longer survival, while single relationship status and history of tobacco use were associated with shorter survival.