SURGICAL-MANAGEMENT OF BRAIN-STEM TUMORS IN CHILDREN - RESULTS AND STATISTICAL-ANALYSIS OF 75 CASES

A study was made of 75 children treated between 1970 and 1990, with partial, subtotal, or total removal of three intrinsic and 72 exophytic or surface brain-stem tumors. In all cases, the goal of surgery was to remove as much tumor as possible. Extent of removal was defined according to data obtained from postoperative computerized tomography or magnetic resonance imaging, and was considered partial when only a small amount of tumor was removed, subtotal when a few cubic millimeters of tumor was left, and total when no residual tumor was seen on postoperative radiological investigations. An ultrasonic aspirator was used for the 43 most recent operations. Among tumor removals without the aspirator, 24 (75%) were partial, eight (25%) subtotal, and none total; with the use of the aspirator, the number of partial removals decreased to 44.5% while that of subtotal and total removals increased to 32% and 23.5%, respectively. There were 69 gliomas (92%) and 47 benign tumors (62.6%). Forty-nine patients were irradiated postoperatively, and 14 of the 23 patients whose benign tumors were removed totally or subtotally did not undergo irradiation. This study showed that: 1) the overall prognosis of patients with malignant tumors was poor and was not improved by surgery; 2) the survival rate of those with benign tumors was significantly (p < 0.01) lower after partial removal than after total or subtotal removal (52% and 94%, respectively, at 5 years); 3) comparison of means and proportions (Student's and chi-squared tests) between benign and malignant tumors showed a significant difference relating to patient age (p < 0.03), peritumoral hypodensity (p < 0.001), and preoperative duration of symptoms (p < 0.001); 4) stepwise logistic regression analysis confirmed that two of these three variables were related to malignancy: namely, patient age at surgery (p < 0.03) and presence of peritumoral hypodensity (p < 0.001); and 5) routine postoperative irradiation was contraindicated after total or subtotal removal of benign tumors.