Cell cycle times of short-term cultures of brain cancers as predictors of survival

Tumour cytokinetics estimated in vivo as potential doubling times (T_pot values) have been found to range in a variety of human cancers from 2 days to several weeks and are often related to clinical outcome. We have previously developed a method to estimate culture cycle times of short-term cultures of surgical material for several tumour types and found, surprisingly, that their range was similar to that reported for T_pot values. As T_pot is recognised as important prognostic variable in cancer, we wished to determine whether culture cycle times had clinical significance. Brain tumour material obtained at surgery from 70 patients with glioblastoma, medulloblastoma, astrocytoma, oligodendroglioma and metastatic melanoma was cultured for 7 days on 96-well plates, coated with agarose to prevent proliferation of fibroblasts. Culture cycle times were estimated from relative ³H-thymidine incorporation in the presence and absence of cell division. Patients were divided into two groups on the basis of culture cycle times of ⩽10 days and >10 days and patient survival was compared. For patients with brain cancers of all types, median survival for the ⩽10-day and >10-day groups were 5.1 and 12.5 months, respectively (P=0.0009). For 42 patients with glioblastoma, the corresponding values were 6.5 and 9.0 months, respectively (P=0.03). Lower grade gliomas had longer median culture cycle times (16 days) than those of medulloblastomas (9.9 days), glioblastomas (9.8 days) or melanomas (6.7 days). We conclude that culture cycle times determined using short-term cultures of surgical material from brain tumours correlate with patient survival. Tumour cells thus appear to preserve important cytokinetic characteristics when transferred to culture.

Gamma knife radiosurgery for the treatment of brain metastases

One hundred and ninety-three patients with brain metastases from various primary sites received Gamma Knife radiosurgery (GKR) from July 1992 to August 1997 and were reviewed to evaluate their clinical outcome. Survival follow-up was available on 173 patients. Whole-brain radiation therapy was also administered to 148 of these patients. The median survival was 13.1 months from initial detection of brain metastases, and 7.5 months from GKR. Univariate and multivariate analyses were performed to determine prognostic factors that influenced survival following GKR. Enhanced survival is observed in patients with radiosensitive tumor types, supratentorial tumor, history of brain tumor resection, controlled primary site, and absent extracranial metastases. Local lesion control was obtained in 82% of the patients according to their last follow-up MRI scan. GKR is an effective means of treating patients with brain metastases.