Clinicohistological study of oligodendroglioma and oligoastrocytoma

From the archives of the AFIP: Oligodendroglioma and its variants: radiologic-pathologic correlation

Oligodendroglioma is the third most common glial neoplasm and most commonly arises in the frontal lobe. It occurs in males more frequently, and the peak manifestation is during the 5th and 6th decades. Children are affected much less commonly. The clinical presentation is often of several years duration with most patients presenting with seizures, reflecting the strong predilection of this tumor to involve the cortical gray matter. Current histopathologic classification schemes recognize two main types of tumors: well-differentiated oligodendroglioma and its anaplastic variant. Less commonly, neoplastic mixtures of both oligodendroglial and astrocytic components occur and are termed oligoastrocytomas, with both well-differentiated and anaplastic forms. Surgical resection is the mainstay of initial treatment, and many patients experience a long progression-free period. Recent genotyping has revealed chromosomal loss of 1p and 19q as a genetic signature in most oligodendrogliomas, and these tumors respond favorably to chemotherapy. Hence, radiation therapy is now generally reserved for partially resected tumors and cases that failed to benefit from chemotherapy. At cross-sectional imaging, the tumor characteristically involves the cortical gray matter and frequently contains calcification. Robust enhancement is not a common feature and suggests transformation to a higher histologic grade. Advanced magnetic resonance imaging techniques and metabolic imaging play increasingly important roles in both pre- and postoperative assessment of these complex neoplasms.

Impact of location on outcome in children with low-grade oligodendroglioma

BACKGROUND

Childhood low-grade oligodendroglioma (WHO grade II) are rare. No controlled pediatric study has been published, to generate high level evidence for the best treatment. Therefore, we retrospectively analyzed data available from pediatric patients.

PROCEDURE

We pooled data from two prospective German multicentre studies (HIT-DOK and HIT-LGG). Eligibility criteria were: (1) primary neoplasm, (2) histology of pure oligodendroglioma WHO grade II, (3) intracranial location, (4) age <18 years, (5) date of diagnosis: 1990-2002, (6) observation time >6 months. The outcome was analyzed by using the SPSS-software.

RESULTS

Nineteen boys and 13 girls were eligible (median age 10.3 years). The tumor locations included: 26 peripheral tumors (23 cerebral hemisphere, 3 cerebellum), and 6 central tumors (4 thalamus, 1 frontal mesencephalon, 1 basal ganglia). Resections were classified as complete in 18 (14 cerebral hemispheres, 3 cerebellum, 1 thalamus) and less than complete in 14 patients (3 subtotal resections, 8 partial resections, 3 biopsy). The 5-year event-free survival (EFS) and overall survival (OS) rates of all patients were 81.3 and 84.4%, respectively (median observation time 3.8 years). All of the 26 children with peripheral tumors were alive with no tumor progression, but five of six patients with central tumors died of disease (median time to death 1.6 years). This survival difference was statistically significant for EFS (P < 0.0001) and OS (P < 0.0001). The difference between completely resected versus incompletely resected tumors was far less striking (P > 0.06).

CONCLUSIONS

The outcome of children with centrally located low-grade oligodendroglioma is particularly poor, while tumors of the cerebral hemispheres and cerebellum carry an excellent prognosis, even with minor tumor resection.

Clinical experiences with oligoastrocytomas WHO grade II and III

Between April 1991 and June 2002, 39 patients with an histologically proven oligoastrocytoma WHO grade II and III were operated on in our department. Twenty-two patients were male and 17 female. Mean age was 42 years (20-67 years). The tumor was localized in the frontal lobe in 22 patients, in the temporal lobe in seven patients, in the parietal lobe in nine patients and in the occipital lobe in one patient. The leading clinical symptoms were seizures in 33 patients. Seventeen patients were operated on under local anesthesia. One operation was performed in 22 patients, two operations in eight, three operations in five, four operations in three and six operations in one patient. Histological examination showed oligoastrocytoma WHO grade II in 12 patients and WHO grade III in 27 patients. Postoperative radiotherapy was performed in 33 patients and chemotherapy in six patients. One female patient developed spinal drop metastases 10 months after the operation. One patient with a primary oligoastrocytoma grade II and five patients with a primary oligoastrocytoma grade III died during follow-up. The follow-up period was between 6 months and 25 years (mean 7 years 6 months).

Clinicopathological study of oligodendroglial tumors: the effectiveness of interferon beta, ACNU/MCNU, and radiation (IAR/IMR) for anaplastic tumors

The retrospective clinicopathological characteristics of oligodendroglial tumors were investigated in patients who underwent surgery, radiotherapy, and/or chemotherapy. Regarding oligodendroglioma and oligoastrocytoma without malignancy, patients who had undergone radiation therapy at a total dose of 40-50Gy had relatively long postoperative survival. Of these 15 patients, 6 showed signs of recurrence, and after additional treatment, 5 patients are still alive. On the other hand, regarding anaplastic oligodendroglial tumors, patients with anaplastic oligoastrocytoma responded well to combination chemotherapy with interferon beta, nitrosourea derivatives (ACNU/ MCNU), and radiation therapy (referred to as IAR/IMR) and survived longer than patients with anaplastic oligodendroglioma. In conclusion, patients with oligodendroglial tumors could survive longer by treatment involving surgery and radiotherapy. As for malignancy, cases of anaplastic oligoastrocytoma could be effectively treated by adjuvant therapy using IAR/IMR after surgery, but in cases of anaplastic oligodendroglioma, the response to IAR/IMR was not good, and another strategy of treatment should be recommended.

Cisplatin and BCNU chemotherapy for anaplastic oligoastrocytomas

In this study 32 newly diagnosed anaplastic oligoastrocytoma patients were enrolled (median age of 41 years, range 19-63; median Karnofsky performance status of 90, range 70-100). All patients were treated with Cisplatin (109 mg/m2) and BCNU (160 mg/m2). The chemotherapy started in the first week after surgery and it was administered every 6 weeks (5 scheduled cycles) for a total of 127 cycles. After the second cycle of chemotherapy all patients received radiotherapy (56.5 Gy). The median follow-up was 63.2 months (10-91). Nine patients were reoperated-on. The median time to tumor progression (TTP) and median survival time (ST) for the whole group of patients were 54.6 and 70.1 months, respectively. A proportional hazard model was used to look at potential prognostic factors for survival including lower age (< 40 years), extent of surgery (total/subtotal versus partial) and reoperation. When we analyzed the group of patients with total/subtotal surgery or age under 40 years the median ST could not be assessed due to the high number of surviving patients after a follow-up of 52 months. The median ST for the older patients or for patients partially operated-on was 54.1 and 42.2 months. In our study only total/subtotal surgery predicted for longer survival (p < 0.001). This schedule of treatment provides durable response in a selected group of anaplastic oligoastrocytoma patients.

Clinicopathologic study of 85 similarly treated patients with anaplastic astrocytic tumors. An analysis of DNA content (ploidy), cellular proliferation, and p53 expression

BACKGROUND

The biologic behavior of anaplastic (World Health Organization Grade III) astrocytomas and oligoastrocytomas is highly variable, ranging from rapid progression to prolonged survival. It is difficult to predict the outcome of an individual patient based on morphology alone.

METHODS

To determine the prognostic value of commonly used clinicopathologic markers, we reviewed our experience with 85 similarly treated patients enrolled in 3 North Central Cancer Treatment Group high grade glioma protocols. The pathology was comprised exclusively of primary anaplastic astrocytic tumors (66 astrocytomas and 19 oligoastrocytomas). Variables examined included patient age, morphologic type, preoperative performance score, extent of surgery, solitary versus multiple mitoses, DNA flow cytometric and image morphometric parameters, and expression of proliferating cell nuclear antigen, MIB-1, and p53 expression.

RESULTS

The study was comprised of 48 men and 37 women ranging in age from 14-79 years (median age, 47 years). Overall survival ranged from <1 month to >12 years (median, 21.6 months). Statistical analyses revealed that age accounted for the majority of this extensive variability in survival. The median survival times were 65. 5 months, 22.1 months, and 4.4 months, respectively, for the groups <40 years, 40-59 years, and >/=60 years, respectively (P < 0.0001). On univariate analyses, aneuploidy by flow cytometry and a low performance score also predicted a better survival (P values of 0.04 and 0.009, respectively). Statistical trends predicting a better survival were observed for patients with a solitary mitosis and p53 immunopositivity. However, only patient age remained significant in multivariate models.

CONCLUSIONS

In a small but relatively uniformly treated cohort of patients with anaplastic astrocytomas and oligoastrocytomas, patient age was associated strongly and inversely with overall survival. Once patient age was taken into account, the clinical and pathologic markers tested appeared to be of limited prognostic value.