44 Outcomes and Quality of Life after Surgery for Meningiomas
Because surgical treatment is the mainstay for most intracranial meningiomas, it is important for neurosurgeons to appreciate the surgical outcome and quality of life after meningioma surgery. Advances in microsurgical technique, neuroimaging modalities, neuroanesthesia, and perioperative intensive care have improved surgical outcome substantially in recent decades. Therefore, most of the surgical outcomes in this chapter are cited from contemporary literature (2000 to present) to depict the outcome of contemporary microsurgery.
Outcomes are usually measured in surgical morbidity, mortality, time to recurrence, and quality of life. Extent of resection, tumor grade, proliferative markers, and tumor location are significant factors in predicting the surgical outcome; we therefore address each of these in detail. It is also important to acknowledge the increasing use of multimodality treatment, including radiation therapy, in the management of certain meningiomas, such as cavernous sinus and petroclival meningiomas. Finally, the importance of quality of life is discussed, with emphasis on the fact that comprehensive evaluation of outcome after meningioma surgery is crucial.
Because surgical resection has long been the preferred definite treatment for most intracranial meningiomas, it is important for neurosurgeons to appreciate the outcome and quality of life after surgery for these patients. In contemporary practice, the goal of surgery for intracranial meningiomas is to achieve as extensive a resection as possible while minimizing neurological morbidity.
Figure 44.1 shows the parameters and interrelationship for surgical, tumor, and patient outcome. In general, the most common factors that influence surgical outcome include the comorbidity and age of the patient, the size and location of the tumor, and the presence and severity of neurological deficit. The measurable parameters for patient outcome include the Karnofsky performance scale (KPS), quality of life (QOL) assessments, biopsychosocial status, complication, and disease status. It is known that a patient may have poor functional outcome or QOL after apparently successful surgery. This fact stresses the importance of addressing biopsychosocial factors to achieve best outcome. Complications include both surgical and medical complications. Surgical complications include infection, hemorrhage, cerebrospinal fluid (CSF) leakage, and wound problems. Medical complications include deep vein thrombosis, seizure, infection, and pulmonary embolism. We expand more on this topic at the end of the chapter, especially with regard to QOL. Surgical outcome is reported in the form of extent of resection, complications, morbidity, and mortality in most series. Factors that influence surgical outcome include tumor location, consistency, and vascularity; and the surgeon’s experience, philosophy, and technique. It is apparent that surgical outcome and other treatment modalities influence disease outcome. This includes recurrence rate, progression-free survival, and overall survival. This is related to the extent of resection, World Health Organization (WHO) grade of the tumor, and proliferative markers. Disease outcome is perhaps the greatest determinant of patient outcome; it is a compilation of all other factors.
It is also necessary to acknowledge that the recent advances in radiosurgery and radiation therapy have created a paradigm shift in the management of intracranial meningiomas. This is especially true with the contemporary management of optic nerve sheath meningiomas, cavernous sinus meningiomas, and petroclival meningiomas. Multimodality treatment is often applied to achieve satisfactory functional outcome and tumor control.
Extent of Resection as Prediction of Outcome
Simpson demonstrated in 1957 that the extent of surgical resection correlated well with late tumor recurrence.3 However, his data were gathered long before microsurgery and present techniques and are based on the surgeon’s assessment of resection. He reported a 9% recurrence rate after total resection along with the dural base (grade I resection), a 19% recurrence rate after total resection with the dural base cauterized (grade II), a 29% recurrence rate when the tumor was removed but the dura could not be resected (grade III), and an ~40% recurrence rate when only subtotal resection was performed (grade IV). Subsequent studies in the magnetic resonance imaging (MRI) era with a follow-up period longer than 5 years have found higher recurrence rates; a 70% recurrence rate after subtotal resection, and 16% and 20% recurrence rates after Simpson grade I and II resections, respectively.4,5 Given this high recurrence rate even after Simpson grade I resections, some authors have recommended “grade 0” resection of a normal dural margin 2 cm wide.6,7 Subsequent retrospective reviews using this surgical method for convexity meningiomas have found no recurrences and no increase in morbidity with this aggressive approach at 5 years.8 However, this approach is impossible in meningiomas other than convexity tumors.
Tumor Grade and Proliferative Markers as Predictors of Outcome
The WHO classification of brain tumors distinguishes three grades of meningiomas: the common type (WHO grade I), the atypical type (WHO grade II), and the ana-plastic type (WHO grade III).9 Using WHO criteria, 81% of intracranial meningiomas were benign, with a 12% 5-year recurrence rate; 15% were atypical, with a 41% 5-year recurrence rate; and 4% were anaplastic brain-invasive with a 56% 5-year recurrence rate after gross total resection.10 In one study of the brain-invasive anaplastic type meningiomas, the 5-year mortality rate was 83% and median survival was only 1.4 years.11 Benign and atypical brain-invasive lesions showed similar 5-year mortality rates of ~25% and between 10 and 14 years median survival. Similar to benign grade I meningiomas, gross total resection of atypical or anaplastic meningioma is associated with lower recurrence rates than with subtotal resection.11 Once recurrence develops, prognosis is poor because of the high likelihood of treatment failure.12
The histopathology is not solely decisive for the outcome with respect to tumor control.13 Molecular markers of prognostic value have been reported, and most studies have shown that an elevated MIB-1 index is useful for assessing growth rate and may be predictive of recurrence and poor outcome.1,12 It has also been demonstrated that the CDKN2A deletion, along with a 9p21 deletion, is a predictor of malignant progression, increased recurrence, and poor survival.14
Surgical Outcome of Meningiomas in Different Locations
Comparing surgical outcome for meningiomas at different sites is difficult because the nomenclature, surgical indication, approach, philosophy, policy for adjuvant radiation, definition of the extent of resection, recurrence, management of recurrence, and follow-up period all differ significantly. The results provided in this chapter are outcomes from centers of excellence in managing intracranial meningiomas and are intended to provide general information for clinicians and patients in terms of surgical outcome.
Surgical morbidity and mortality have declined steadily as a result of the refinements of microsurgical technique, advancement in neuroanesthesia, and improved peri-operative intensive care. Therefore, most of the surgical outcomes in this chapter are cited from contemporary references (2000 to present). Table 44.1 provides contemporary surgical outcome according to location of intracranial meningioma. Outcomes with multimodality treatment for petroclival and cavernous sinus meningiomas are provided, given that multimodality treatment is the current trend in management of these difficult lesions.
Joung and Lee formulated a “CLASS” algorithm based on c omorbidity, tumor l ocation, patient a ge, tumor s ize, and neurological s igns and s ymptoms to assess the risk of meningioma surgery.15 Tumor location was classified into low-, moderate-, and high-risk groups. The low-risk group included convexity, lateral and middle sphenoid wing, and posterior petrous meningiomas. The moderate-risk group included olfactory groove, planum sphenoidale, tentorial (lateral/paramedian), parasagittal, falcine, intraventricular, cerebellopontine angle, posterior/lateral foramen magnum, and parasigmoid/paratrans-verse sinus meningiomas. The high-risk group included clinoidal, medial sphenoid ridge, cavernous sinus, tuberculum sellae, tentorial (medial/incisural), ventral petrous, anterior/lateral foramen magnum, and petroclival meningiomas. Professor Kawase and his group (Adachi et al) at Keio University have created a simple algorithm, the “ABC” system, for assessing risk in skull base meningioma surgery based on preoperative image findings.16 This system takes a ttachment/size, a rterial involvement, relation to b rain stem, and c ranial nerve involvement into account and was found to predict the probability of radical surgical removal.
Olfactory Groove and Planum Sphenoidale Meningiomas
Hentschel and DeMonte reported 13 patients with olfac-tory groove meningiomas surgically treated at the M.D. Anderson Cancer Center in 2003.17 Complete resection, including hyperostotic bone and dura of the cribriform plate and any extension into the ethmoid sinuses, was achieved in 11 patients. There was no surgically related complication and there was no recurrence in a mean follow-up period of 2 years. However, this is too short an interval to be definitive. Nakamura et al reported 82 cases of olfactory groove meningiomas surgically treated by the senior author Samii.18 Gross total tumor resection was accomplished in 92% of the cases. The overall recurrence rate was 4.9% in a median follow-up period of 5.3 years. It has been reported that the cranial base and paranasal sinuses are sites of predilection for recurrence of olfactory groove meningiomas.19 Complications included subdural hygroma (17.6%), seizure (11.8%), hydrocephalus (5.8%), hemorrhage (2.9%), and brain edema (2.9%). The perioperative mortality was 4.9%.
Surgical outcome of patients with preoperative visual impairment or mental status changes related to these lesions is frequently satisfying20; Nakamura et al reported preoperative visual disturbance improved in 55% of patients, dementia improved in 62.9% of patients, and concentration difficulties improved in 68.3% of patients.18 Hentschel and DeMonte reported 100% improvement in mental dysfunction and 83% improvement in visual disturbance.17 Preservation of olfactory function was more likely in cases with tumor size less than 3 cm and normal preoperative function.21
Tuberculum Sellae Meningiomas
Tuberculum sellae meningiomas present a special challenge because of their proximity to arteries of the anterior circulation, optic apparatus, and hypothalamus. The overall morbidity and mortality rate associated with resection of these tumors has decreased substantially in modern series. Total resection can be achieved in 76.4—93% of the cases, with a 15 to 20% incidence of nonvisual morbidity and 0 to 8.7% mortality.22–29 Preservation of vision is the most important goal of surgery, and improvement in vision has been reported in 40 to 80% of the patients.24,29–31 Nakamura et al reported 72 cases of tuberculum sellae meningiomas surgically treated by the senior author Samii.32 Total resection was achieved in 91.7% of the patients. The perioperative mortality rate was 2.8%. Postoperative visual improvement was seen in 65% of patients. Visual improvement was dependent on the duration of preoperative visual symptoms but not on preoperative visual acuity or tumor size. Patients with a visual symptom duration of less than 6 months tend to recover more than those with a duration longer than 1 year. The overall recurrence rate was 2.8% during a mean follow-up time of 3.8 years. Although most patients will have favorable visual outcome, it is noteworthy that visual deterioration has been reported in 17 to 20% of patients receiving surgery for these lesions.
The long-term visual outcome for these patients has improved substantially compared with early series. However, tumor recurrence is still common, even when gross total resection was achieved. One study demonstrated a 39% recurrence rate with a mean follow-up time of 10.7 years.33 Patients with tumor recurrence are likely to lose vision in at least one eye and are unlikely to have visual improvement with subsequent surgery or radiation therapy. Therefore, postoperative patients should undergo long-term, serial clinical and radiological examination to allow early detection and management of recurrences. Some have reported the extended transsphenoidal approach for resection of these tumors.34 This procedure is suitable for small midline lesions, without major vessel encasement or parasellar extension. Improvement of vision was seen in 75% of the cases, and 93.1% had gross total tumor removal. However, the difficulty in reconstructing the cranial base dural and bone defects has to be overcome because the postoperative cerebrospinal fluid leakage rate was as high as 28.6%.34
Optic Nerve Sheath Meningiomas
It has been shown that fractionated stereotactic radio-therapy should be considered the treatment of choice for the majority of patients with these tumors because of its capability of achieving excellent local control and improved/stable visual function in more than 80% of patients. This is especially true for patients with progressive functional loss and most patients with some degree of functional loss at presentation. The proper timing for patients with no or slight vision loss at presentation should be further investigated, however.35
Surgical management includes biopsy, optic nerve sheath fenestration, and tumor excision. Because surgical management is rarely applied for these tumors, we will only review the indication and result in brief. Biopsy, which was used in the past, frequently leads to functional impairment. Due to the characteristic clinical presentation, funduscopic and radiological findings of these tumors, biopsy is currently regarded as unnecessary for the clinical diagnosis. Optic nerve sheath fenestration has been shown effective in arresting progressive visual loss by some, whereas some others found it unsuccessful.35,36 Some even report this procedure might result in orbital invasion of the tumor, which necessitates orbital exenteration. This approach has therefore largely been abandoned. Tumor excision was a frequently practiced treatment approach in the last decade. Orbital approaches provide adequate resection for selected localized cases, whereas most cases require a transcranial approach to provide complete tumor resection up to the optic chiasm. Dutton reviewed 148 surgically treated cases in 1992 and reported that the transcranial approach is associated with zero mortality, 30% morbidity, and a recurrence rate of 25%.37 Importantly, improvement of vision occurred in only 5% of patients, and 94% of patients suffered from visual deterioration. In most cases, blindness occurred due to the interruption of pial vessels and ischemic injury to the optic nerve, given that these tumors and the optic nerve share the same blood supply. Currently, transcranial surgery might be indicated for tumors with intracranial spread or continuously progressing large tumors in nonfunctioning eyes to prevent major intracranial spread.
The overall prognosis for these tumors is excellent, with minimal morbidity and mortality. In our series of 163 surgically treated patients reported in 2008, the operative mortality rate was 0%. The incidence of new neurological deficit was 1.7%, and the overall complication rate precluding medical complications was 9.4%.38 It has been stressed that preservation of the cerebral venous system is a key to successful outcome in the surgical management of convexity meningioma. The 5-year recurrence rate for benign meningiomas was 1.8%, atypical meningiomas 27.2%, and anaplastic meningiomas 50%.38 Because total excision could be achieved in all cases, the recurrence rate was largely dependent on the grade of the tumor.
Parasagittal and Falcine Meningiomas
Management of sinus involvement is an important issue. In 2006, Sindou and Alvernia reported 92 patients who underwent aggressive resection of the invaded superior sagittal sinus with venous reconstruction and postoperative anticoagulation.41 They reported a 4% recurrence rate with a mean follow-up period of 8 years, which is low compared with the rates from other series (4% vs 11 to 24%). In their study, there was 3% mortality, and 8% of the patients had permanent neurological deficit, likely due to venous infarction. DiMeco et al reported 108 patients harboring parasagittal meningiomas that invaded the superior sagittal sinus who were surgically treated at their institute in 2004.40 They recommend that if the sinus is invaded, it can be opened for resection of the tumor to attempt to preserve the patency of the sinus. Complete resection of the tumor and sinus can be performed in patients with sinus obstruction. With this approach it is not necessary to reconstruct the sinus, and tumor recurrence rate was 13.9% with a median follow-up period of 6.6 years. The mortality rate was 1.8%, and the complication rate was 10.1%. In our series of 46 consecutives cases reported in 2008, we proposed a less aggressive surgical approach; tumor was resected up to the sinus wall, and the sinus was left intact.39 Residual tumor was followed up and treated with radiosurgery at recurrence. Although this approach led to a substantial number of patients with postoperative residual tumors (36.8%), only three WHO grade I meningiomas (7.7%) progressed. The recurrence-free survival was 94.7% at 5 years. In our series, 55.6% of patients with a preoperative neurological deficit had recovery, and 5.5% had a new deficit. One elderly patient died of a pulmonary embolus within 1 month of surgery.
The recent advance in radiosurgical technique provides an alternative treatment paradigm to radical surgery; subtotal resection with adjuvant radiosurgery or with radiosurgery alone. Few studies have focused on the parasagittal meningioma in this regard. However, there is accumulating evidence showing that midline meningiomas have a higher incidence of symptomatic brain edema after radiosurgery, which might be related to venous thrombosis.42 Recently, it has been shown that this effect is seen less in patients with parasagittal meningioma treated with fractionated radiotherapy.43