Early computed tomographic scanning after resection of brain tumors in children

Spontaneous regression of cerebellar astrocytoma after subtotal resection

CASE REPORT

The authors report a child in whom residual cerebellar astrocytoma after surgical resection was documented on serial computed tomography scans to undergo gradual complete regression spontaneously over a period of 11 years. In this case, the time course of regression has been well documented.

CONCLUSION

The time course of regression may provide clues as to the underlying cause of this phenomenon.

Postoperative imaging after brain tumor resection

Prognosis after surgery for a brain tumor is not only influenced by its histology but also by the completeness of resection. The exact identification of a possible residual tumor is crucial also for follow-up and the purpose of evaluation of response to treatment. A review of the current and past literature addressing the individual value, the technique, and the pitfalls of postoperative imaging with Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) for the definition of a postoperative residue after the resection of brain tumors is given. The different problems and possibilities are illustrated by imaging examples.

Surveillance neuroimaging in childhood intracranial ependymoma: how effective, how often, and for how long?

OBJECT

The authors examined images obtained in 52 children with intracranial ependymomas to determine risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcome.

METHODS

Data obtained in all children with intracranial ependymomas were prospectively entered into a database from January 1987 to June 2000. The imaging and clinical details in all patients were reviewed. Fifty-two children with histologically proven intracranial ependymomas were treated at the authors' institution; recurrences developed in 28 (54%) of them, with a median time from surgery to first recurrence of 14.5 months (range 3-65 months). Of these tumor recurrences, 43% were asymptomatic and were noted on surveillance imaging. Seventeen children died, all of whom had recurrences. Incomplete excision of the primary tumor was significantly associated with reduced time to recurrence (p = 0.0144) and time to death (p = 0.0472). The age of the patient, location of the primary tumor, histological findings, and the presence or absence of spinal metastases on preoperative imaging were not significantly associated with outcome. The risk of death at any given time was 12-fold greater in patients in whom a recurrence was identified due to symptoms rather than on surveillance images (p = 0.016).

CONCLUSIONS

Recurrent childhood ependymoma has a poor prognosis. The extent of the initial local tumor resection is the factor most closely associated with outcome. Surveillance imaging reveals a substantial number of asymptomatic recurrences, and survival appears to be improved in these patients compared with those identified by symptoms. The improvement in survival is thought to be greater than that expected just from earlier diagnosis.

Post-operative computed tomography in two dogs with cerebral meningioma

Post-operative computed tomography (CT) has been described as a technique for diagnosing incomplete resection or recurrence of cerebral neoplasms in humans. The characteristics of immediate postoperative CT images in dogs with intracranial pathology are unknown. This report describes findings from preoperative, immediate post-operative, and 4 week to 9 month follow-up CT examinations in two dogs with histologically-confirmed cerebral meningiomas. In images of one dog after surgery there was mild contrast enhancement of the tissue surrounding the surgical site. This enhancement had resolved in later images and was probably the result of surgically induced trauma. In post operative images of the other dog there was significant hyperattenuation of the tissues around the surgical site. In post contrast images there was increased enhancement that was evident in later images. These findings, although not supported by necropsy, probably indicate incomplete excision of the tumor.

Current neurosurgical management and the impact of the extent of resection in the treatment of malignant gliomas of childhood: a report of the Children's Cancer Group trial no. CCG-945

OBJECT

One hundred seventy-two children with high-grade astrocytomas were treated by members of the Children's Cancer Group in a prospective randomized trial designed to evaluate the role of two chemotherapy regimens. Seventy-six percent of the patients (131 children) in whom a diagnosis of either anaplastic astrocytoma or glioblastoma multiforme was confirmed by central pathological review are the subject of this report.

METHODS

Patients were stratified according to the extent of tumor resection (biopsy [< 10%], partial resection [10-50%], subtotal resection [51-90%], near-total resection [> 90%], and total resection) as determined by surgical observation and postoperative computerized tomography scanning. Information on contemporary neurosurgical management was obtained from the patient's operative records and standardized neurosurgical report forms. The vast majority of tumors were supratentorial: 63% (83 tumors) in the superficial cerebral hemisphere, 28% (37 tumors) in the deep or midline cerebrum, and only 8% (11 tumors) in the posterior fossa. A significant association was detected between the primary tumor site and the extent of resection (p < 0.0001). A radical resection (> 90%) was performed in 37% of the children: 49% of the tumors in the superficial hemisphere and 45% of tumors in the posterior fossa compared with 8% of midline tumors. Tumor location could also be used to predict the need for both temporary and permanent cerebrospinal fluid (CSF) diversion. Half of the deep tumors and 8% of the hemispheric astrocytomas ultimately required a permanent CSF shunt. Improvement in preoperative neurological deficits and level of consciousness was seen in 36% and 34% of the children, respectively. New or increased deficits were present in 14% of the children, with 6% experiencing a diminished sensorium after surgery. Postoperative nonneurological complications were rare: infection, hematoma, and CSF fistula each occurred in 1.7% of the children. Univariate and multivariate analyses demonstrated that radical tumor resection (> 90%) was the only therapeutic variable that significantly improved progression-free survival (PFS) rates. For all patients with malignant astrocytomas, the distributions of PFS rates were significantly different (p = 0.006) following radical resection compared with less extensive (< or = 90%) resection. The 5-year PFS rates were 35 +/- 7% and 17 +/- 4%, respectively. The differences in the distribution of PFS rate were significant for the subsets of patients with anaplastic astrocytoma (p = 0.055) and glioblastoma multiforme (p = 0.046). The 5-year PFS rates for anaplastic astrocytoma were 44 +/- 11% and 22 +/- 6% for cases in which the tumor was radically resected and less than radically resected, respectively; whereas the 5-year PFS rates for glioblastoma multiforme were 26 +/- 9% and 4 +/- 3% for cases in which the tumor was radically resected and less than radically resected, respectively.

CONCLUSIONS

The demonstration of a survival advantage provided by radical resection should prompt neurosurgeons to treat malignant pediatric astrocytomas with aggressive surgical resection prior to initiation of radiotherapy or adjuvant chemotherapy.

Current neurosurgical management and the impact of the extent of resection in the treatment of malignant gliomas of childhood: a report of the Children's Cancer Group Trial No. CCG-945

Object

One hundred seventy-two children with high-grade astrocytomas were treated by members of the Children's Cancer Group in a prospective randomized trial designed to evaluate the role of two chemotherapy regimens. Seventy-six percent of the patients (131 children) in whom a diagnosis of either anaplastic astrocytoma or glioblastoma multiforme was confirmed by central pathological review are the subject of this report.

Methods

Patients were stratified according to the extent of tumor resection (biopsy [< 10%], partial resection [10-50%], subtotal resection [51-90%], near-total resection [> 90%], and total resection) as determined by surgical observation and postoperative computerized tomography scanning. Information on contemporary neurosurgical management was obtained from the patient's operative records and standardized neurosurgical report forms.

The vast majority of tumors were supratentorial: 63% (83 tumors) in the superficial cerebral hemisphere, 28% (37 tumors) in the deep or midline cerebrum, and only 8% (11 tumors) in the posterior fossa. A significant association was detected between the primary tumor site and the extent of resection (p < 0.0001). A radical resection (> 90%) was performed in 37% of the children: 49% of the tumors in the superficial hematoma and 45% of tumors in the posterior fossa compared with 8% of midline tumors. Tumor location could also be used to predict the need for both temporary and permanent cerebrospinal fluid (CSF) diversion. Half of the deep tumors and 8% of the hemispheric astrocytomas ultimately required a permanent CSF shunt.

Improvement in preoperative neurological deficits and level of consciousness was seen in 36% and 34% of the children, respectively. New or increased deficits were present in 14% of the children, with 6% experiencing a diminished sensorium after surgery. Postoperative nonneurological complications were rare, infection, embolization, and CFS fistula each occurring in 1.7% of the children.

Univariate and multivariate analyses demonstrated that radical tumor resection (> 90%) was the only therapeutic variable that significantly improved progression-free survival (PFS) rates. For all patients with malignant astrocytomas, the distributions of PFS rates were significantly different (p = 0.006) following radical resection compared with less extensive (¾ 90%) resection. The 5-year PFS rates were 35 ± 7% and 17 ± 4%, respectively. The differences in the distribution of PFS rate were significantly different for the subsets of patients with anaplastic astrocytoma (p = 0.055) and glioblastoma multiforme (p = 0.046). The 5-year PFS rates for anaplastic astrocytoma were 44 ± 11% and 22 ± 6% for cases in which the tumor was radically resected and less than radically resected, respectively; whereas the 5-year PFS rates for glioblastoma multiforme were 26 ± 9% and 4 ± 3% for cases in which the tumor was radically resected and less than radically resected, respectively.

Conclusions

The demonstration of a survival advantage provided by radical resection should prompt neurosurgeons to treat malignant pediatric astrocytomas with aggressive surgical resection prior to initiation of radiotherapy or adjuvant chemotherapy.

Posterior fossa duraplasty in children: remarks on surgery and clinical and CT follow-up

A series of 314 posterior fossa duraplasties in children were performed at the Department of Neurosurgery, Hradec Králové, over the past 33 years. Computed tomographic (CT) imaging was used to compare the healing of various kinds of collagenic dural substitutes--allogeneic fascia lata, allogeneic dura mater and xenogeneic pericardium. Early (8 days to 3 months following surgery) and late (1-18 years following surgery) axial CT scans with sagittal reconstruction for duraplasty in 55 children were evaluated. In early postoperative CT scans, epidural collections of cerebrospinal fluid, sanguinolent liquid or haematoma and/or pseudocysts or pseudomeningoceles appeared. In late CT follow-up, calcifications and ossifications in the "suboccipital coverings complex" (SCC) gradually developed and pseudocysts or pseudomeningoceles rarely persisted. It is concluded, on the basis of perioperative, clinical, and CT examinations, that posterior fossa duraplasties in children formed an important anatomical barrier and regardless of the type of graft had a favourable outcome; CT was shown to be a suitable method for the demonstration of dural grafts at the site of craniectomies.