['Radical surgical resection of cerebral meningiomas involving the dura mater of venous sinuses is challenging, and tumor residuals are frequently left after surgery. This study sought to evaluate the effect of adjuvant stereotactic radiosurgery (aSRS) on the time to significant growth of meningioma residuals requiring retreatment.', 'A total of 119 consecutive patients (2004-2013) receiving primary surgical treatment for a meningioma in proximity to a venous structure were included. The patients were assessed retrospectively, with a focus on retreatments and mortality. Radicality of initial tumor surgery was scored using postoperative magnetic resonance imaging. Three subgroups were identified: 1) radical total resection (RTR); 2) near-total resection (NTR), followed by aSRS (NTR\xa0+ aSRS); and 3) NTR but no aSRS (NTR\xa0- aSRS). In the NTR\xa0- aSRS group, intervention was initiated after radiologic (magnetic resonance imaging) findings verified growth of residual tumor, in contrast to the NTR\xa0+ aSRS group, which received aSRS before regrowth. Time to first retreatment, progression-free survival (PFS), and overall survival were analyzed with the log-rank test and multiple-events Cox regression.', 'RTR was associated with the best prognosis. The patients in the NTR\xa0+ aSRS group had significantly longer time to first retreatment compared with NTR\xa0- aSRS patients (P < 0.001). There was also a significant difference in mortality (P < 0.05) and a tendency to prolonged PFS (P\xa0=\xa00.07) in the NTR\xa0+ aSRS group. The Cox regressions confirmed the positive effects of NTR\xa0+ aSRS on time to retreatment (hazard ratio, 7.3; P < 0.01) and PFS (hazard ratio, 3.69; P\xa0= 0.055).'] Does adjuvant Stereotactic Radiosurgery reduce Need for Retreatments in Patients with Meningioma Residuals?