Recurrence of Skull Base Meningiomas: The Role of Aggressive Removal in Surgical Treatment

Benefits of re-do surgery for recurrent intracranial meningiomas

Meningiomas are the most common intracranial extra-axial tumor. While the literature is abundant on the therapeutic management of meningioma recurrence after the initial surgery, the natural history of repeated recurrences is poorly described, as well as and their respective management. A partly retrospective, partly prospective review was conducted in a Norwegian cohort of 1469 consecutive cases of meningioma surgically treated, totaling 11 414 patient-years of follow-up. 114 recurrences (7.7%) were treated surgically with a risk a surgical retreatment of 1% per patient-year of follow-up. 36 patients were operated on 3 times or more. The time-to-retreatment (TTR) decreased significantly and steadily between surgeries, from 4.3 ± 4 years after the first surgery to 2.4 ± 2.9 years after the third surgery. The primary driver for recurrence was the WHO grade (OR 7.13 [4.40;11.55], p < 0.001 for the first recurrence and OR 4.13 [1.49;12.15], p 0.008 for the second), the second predictive factor being a skull base location (OR 2.76 [1.95;3.99] p < 0.001 and OR 0.24 [0.09;0.65], p0.006 respectively). The rates of postoperative hematomas and infections were not influenced by the number of surgeries, whereas the rate of postoperative neurological worsening increased from 3.9% to 16.6% and 13.9%, respectively, after the first, second, and third surgeries. We observed that the TTR decreased significantly between surgeries in patients requiring repeated resections, indicating that surgical treatment of recurrences does not reset the clock but is indeed a "race against time". This should be considered when assessing the benefit-to-risk ratio of patients undergoing repeated surgeries for a recurrent meningioma.

Lateral sphenoid wing meningiomas without bone invasion-still skull base surgery?

Sphenoid wing meningiomas are generally considered as skull base meningiomas (SBMs). However, given their surgical similarities with non-skull base meningiomas (NSBMs), we hypothesized that lateral sphenoid wing meningiomas (LSWMs) without bone invasion (BI) should be considered as NSBMs. N = 65 LSWMs without BI operated between 1990 to 2010 at a single-center were compared to N = 352 NSBMs, represented by convexity meningiomas (CMs), and to N = 23 SBMs, represented by spheno-orbital meningiomas (SOMs), with respect to baseline demographics, clinical presentations, Simpson grades, complications, adjuvant therapies, as well as overall survival (OS) and progression-free survival (PFS). Only WHO grade I meningiomas were included. No significant differences in baseline demographics, clinical presentation, or pre-operative KPS were found between the three groups. Simpson grade 1-3 was achieved in 90.1% of LSWMs, 97.1% in CMs (p = 0.05), and 82.6% in SOMs (p = 0.23). There were no significant differences in postoperative infection, hematoma, neurological worsening, 30-day mortality, or OS between the three groups. Lower re-treatment rates were observed in LSWMs and CMs compared to SOMs (p = 0.06). With respect to PFS, there was no significant difference between LSWMs and CMs (89.1% and 88.5% at 5 years, respectively), whereas PFS was significantly higher in LSWMs than in SOMs (79% at 5 years) (p = 0.05). LSWMs without BI should be considered as an intermediate entity between NSBMs and SBMs. LSWMs are similar to SOMs with respect to extent of resection, but more similar to CMs with respect to re-treatment rates and PFS.

Extent of Resection in Meningioma: Predictive Factors and Clinical Implications

Meningiomas present as intracranial extra-axial lesions with dural attachment, which are primarily managed surgically. The extent of resection (EOR) may vary depending on patient- and tumor-related factors. The aim of this study is to identify preoperative predictive factors of EOR and to propose an estimation of the predicted gross total resection (GTR) based of patient- and tumor-characteristics. 1469 patients from a retrospectively (1990 to 2002) and prospectively managed (2003 to 2010) databank of Oslo University Hospital, Norway, totalling 11,414 patient-years of follow-up were included. Patients had a mean age at surgery of 64 ± 20.1 years with a female-to-male ratio was 2.4:1 and a mean KPS of 81.2 ± 12.1. Skull-base meningiomas represented 47% of all cases. WHO grades were I in 92.3%, II in 5.2%, and III in 2.2%. Bone infiltration was described in 18.7% of cases. 39.3% of patients had Simpson I resection, 34.3% had Simpson II, 5.4% had Simpson III, 20.6% had Simpson IV, and 0.5% had Simpson V. The risk factors for incomplete resection were: symptomatic presentation (OR 0.56 [0.43-0.72]), skull-base location (OR 0.79 [0.70-0.88]), and bone invasion (OR 0.85 [0.73-0.99]). Using a recursive partitioning analysis, we propose a classification-tree for the prediction of GTR rate based on preoperatively determinable patient- and tumor characteristics. The identification of preoperative predictors of poor GTR rate may aid clinicians managing meningioma patients. In selected cases were the predicted GTR rate is low, staged treatment with surgical debulking followed by adjuvant therapy may be favored in order to minimize postoperative morbidity and mortality.

Skull base versus non-skull base meningioma surgery in the elderly

To compare outcomes after surgery for skull base meningiomas (SBMs) with non-skull base meningiomas (NSBMs) in the elderly. Overall, 128 consecutive patients ≥ 70 years of age with intracranial SBMs operated between 1990 and 2010 were compared to 193 consecutive patients ≥ 70 years of age with NSBMs operated within the same time period. Median age at surgery was 75.0 years (mean 75.7, range 70.0-92.4). Follow-up was complete with median 4.7 years (mean 5.5, range 0-19). The female-to-male ratio was 2.8 for SBMs and 1.3 for NSBMs (p < 0.005). The groups had similar preoperative KPS (median 80, range 20-100), but SBMs presented significantly more frequently with raised ICP (RR = 2.2, p < 0.005) and less frequently with seizures (RR = 0.6, p < 0.05). WHO I was significantly more frequent in SBMs (p < 0.005). Gross-total resection (GTR) was less frequent in SBMs (63 vs 82%) (RR = 2.1, p < 0.0001). SBMs were similar to NSBMs with respect to neurological outcome at 6-12 months, reoperations for hematomas, postoperative infections, and 30-day mortality. Retreatment rates and time to retreatments were also similar. There were no differences between the two groups with respect to risk of retreatment and overall survival (OS) at 5, 10, 15, and 20 years. In elderly patients with SBMs selected to surgical treatment, the risks of surgery, risk of retreatment, and OS were similar to NBSMs. Therefore, surgery for SBMs may be considered as safe as NSBMs in the elderly population.

Meningiomas: skull base versus non-skull base

To identify differences between skull base meningiomas (SBM) and non-skull base meningiomas (NSBM). All adult patients (18.0-69.9 years) operated for intracranial meningiomas between 1990 and 2010 at our institution were investigated. Al-Mefty's definition was used to dichotomize tumors into SBM and NSBM. Overall, 1148 consecutive patients were identified. Median age at surgery was 54.2 years [18.1-69.9]. Median follow-up was 7.4 years [0.0-20.9]. There were 562 patients (49%) with SBM and 586 (51%) with NSBM. The two groups were similar with respect to patient age, follow-up time, and number of patients. Overall female-to-male ratio was 2.6:1, but 3.2:1 in SBM and 2.2:1 in NSBM (p < 0.005). With respect to presenting symptoms, SBMs had more often neurological deficits (risk ratio (RR) 1.4; p < 0.0001) and less often seizures (RR 0.4; p < 0.0001). Gross total resections were less frequent in SBM than NSBM (62 vs 84%) (RR 1.3; p < 0.0001). SBMs had a lower risk of WHO grades II and III histology (4.5 vs 9.5%) (RR 0.5; p < 0.001). Worsening of neurological function was more frequent in SBM (21 vs 121%) (RR 1.8; p < 0.001). Retreatment-free survival at 5, 10, and 15 years, respectively, was 80, 70, and 62% for SBM versus 90, 82, and 74% for NSBM (p < 0.0001). Overall survival at 5, 10, and 15 years, respectively, was 93, 85, and 78% for SBM and 96, 91, and 79% for NSBM (p = 0.14). Patients with SBMs had more new-onset neurological deficits and significantly shorter retreatment-free survivals, but this did not adversely affect the overall survival.