Proliferation and aneusomy predict survival of young patients with astrocytoma grade II

Ki-67 is a valuable prognostic factor in gliomas: evidence from a systematic review and meta-analysis

Ki-67 has been widely used as an indicator of cell proliferation in gliomas. However, the role of Ki-67 as a prognostic marker is still undefined. Thus, we conducted a meta-analysis of the published literatures in order to clarify the impact of Ki-67 on survival in glioma cases. Eligible studies were identified in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, Science Direct and Wiley Online Library with the last search updated on August 31, 2014. The clinical characteristics, overall survival (OS) and progression- free survival (PFS) together with Ki-67 expression at different time points were extracted. A total of 51 studies, covering 4,307 patients, were included in the current meta-analysis. The results showed that overexpression of Ki-67 can predict poor OS (HR=1.66, 95%CI: 1.53-1.80; Z=11.87; p=0.000) and poor PFS (HR=1.67, 95%CI: 1.47-1.91; Z=7.67; p=0.000) in gliomas. Moreover, subgroup analyses also indicated that high level of Ki-67 expression was related to poor OS and PFS in glioma patients regardless of region, pathology type, cut-off value and statistical method. In conclusion, the current meta-analysis revealed that Ki-67 expression might be a predicative factor for poor prognosis of glioma patients, emphasizing its importance as a predictor.

Spontaneous regression of residual low-grade cerebellar pilocytic astrocytomas in children

BACKGROUND

Cerebellar low-grade astrocytomas (CLGAs) of childhood are benign tumours and are usually curable by surgical resection alone or combined with adjuvant radiotherapy.

OBJECTIVE

To undertake a retrospective study of our children with CLGA to determine the optimum schedule for surveillance imaging following initial surgery. In this report we describe the phenomenon of spontaneous regression of residual tumour and discuss its prognostic significance regarding future imaging.

MATERIALS AND METHODS

A retrospective review was conducted of children treated for histologically proven CLGA at Great Ormond Street Hospital from 1988 to 1998.

RESULTS

Of 83 children with CLGA identified, 13 (15.7%) had incomplete resections. Two children with large residual tumours associated with persistent symptoms underwent additional treatment. Eleven children were followed by surveillance imaging alone for a mean of 6.83 years (range 2-13.25 years). Spontaneous tumour regression was seen in 5 (45.5%) of the 11 children. There were no differences in age, gender, symptomatology, histological grade or Ki-67 fractions between those with spontaneous tumour regression and those with progression. There was a non-significant trend that larger volume residual tumours progressed.

CONCLUSIONS

Residual tumour followed by surveillance imaging may either regress or progress. For children with residual disease we recommend surveillance imaging every 6 months for the first 2 years, every year for years 3, 4 and 5, then every second year if residual tumour is still present 5 years after initial surgery. This would detect not only progressive or recurrent disease, but also spontaneous regression which can occur later than disease progression.

Low-grade gliomas in adults

Adult patients with a magnetic resonance scan suggestive of a supratentorial low-grade glioma should generally undergo at least a stereotactic biopsy to confirm the diagnosis and rule out an anaplastic glioma or a non-neoplastic lesion. Early tumor treatment should be given to patients with newly diagnosed low-grade gliomas who are over age 50 years, those who have headaches or neurologic deficits other than seizures, or those whose neuroimaging studies show tumor growth or mass effect. For younger patients presenting with seizures and no other neurologic symptoms, it is reasonable to defer therapy until there is clinical or radiographic tumor progression. When it is judged that intervention is necessary, patients should undergo the maximal surgical tumor resection, which preserves or improves neurologic function. For younger (<50 years) astrocytoma patients with a good tumor resection, radiation may be deferred until tumor progression. Early radiation should be given to astrocytoma patients who are older than 50 years of age at diagnosis (regardless of the type of surgery) or to younger patients who are judged to require early intervention but who are not candidates for aggressive surgical resection. The radiation dose for low-grade glioma should be 4500 to 5000 cGy, preferably with three-dimensional conformal ports. The same guidelines for management apply to patients with low-grade oligodendroglioma or oligoastrocytoma, except that chemotherapy is a reasonable alternative to radiation when it is judged that treatment other than surgical resection is required.

Supratentorial grade II astrocytoma: biological features and clinical course

Because of its unpredictable clinical course, treatment strategies for low-grade (grade II) astrocytoma vary from "wait and see" to gross tumour resection followed by immediate radiotherapy. Clinical studies on grade II astrocytoma show that 5-year-survival ranges from 27% to 85% of patients with very few consistent prognostic variables besides the patient's age and the presence of neurological deficit. There is no universally recognised choice of therapy for patients with astrocytoma grade II, partly because of the shortcomings of histological classification systems. Routine microscopy tends to underestimate malignancy grading of astrocytomas and in most cases cannot distinguish between indolent and progressive subtypes. Recent studies suggest that proliferation and genetic markers can be used to identify subgroups of astrocytoma grade II with a rapid progressive clinical course. Therefore these markers should be included in ongoing and future clinical studies of patients with astrocytoma grade II.