Presence of a Malignant Tumor as a Novel Predictive Factor for Repeated Recurrences of Chronic Subdural Hematoma.

BACKGROUND: Various risk factors for recurrence of chronic subdural hematomas (CSDHs) have been reported, including alcohol addiction and diabetes mellitus. However, the significance of malignant tumors with respect to CSDH recurrence remains unclear.

METHODS: We retrospectively evaluated 281 patients with a first-time CSDH from 2006 to 2016. The difference in the recurrence rate within 100 days postoperatively was compared between patients with a past or present extracranial malignant tumor and those with neither a past nor present extracranial malignant tumor at presentation. Patients in the former group were further divided into 2 subgroups: those with present tumors and those with past tumors. Statistical significance was defined as P < 0.05.

RESULTS: A significantly greater repeated recurrence rate (>2 recurrences) was observed in patients with than without a past or present malignant tumor (8.5% vs. 1.7%, respectively; P = 0.01); no significant difference in the first recurrence rate was observed (19.1% vs. 16.2%, respectively; P = 0.63). Furthermore, patients with a present malignant tumor showed a marginally increased repeated recurrence rate than did patients with a past malignant tumor (20.0% vs. 3.1%, respectively; P = 0.053). In the multivariate analysis, a monolayer hematoma was the only risk factor for first recurrence (odds ratio, 3.16; P = 0.003), while a present malignant tumor was the only significant risk factor for repeated recurrences (odds ratio, 16.49; P = 0.002).

CONCLUSIONS: The presence of a malignant tumor can be a novel predictive factor for repeated CSDH recurrences. Patients with malignant tumors should be carefully followed, and treatment options such as subcutaneous reservoir placement may be considered to prevent further recurrences.