Purpose: The disappointing results of chemotherapy in glioblastoma might be caused by the choices of agents, which mostly include nitrosurea. We compared the in vitro efficacy of chemotherapeutic agents, developing a method to summarize published data.
Method: Between 1966 and 1995 chemotherapy in glioma cells was reported in 1643 articles. Efficacy was mostly described by the drug concentration that killed 50% of the cells (LC50). It was measured with various cell-culture techniques, of which a colorimetric test [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltrazolium bromide] was mostly used. We calculated factors from these data to transform results to LC50 values as if the colorimetric test was used in all of them. This allowed data from all publications to be summarized in a new type of meta analysis.
Results: The most important agents and the average LC50 values (mg/l) were actinomycin-D 0.042, vincristine 0.075, mitoxantrone 0.12, vinblastine 0.21, doxorubicin 0.29, diaziquone 0.76, cisplatin 1.1, methotrexate 1.1, cytasine arabinoside 1.59, 5-flurouracil 2.33, bleomycin 18.6, carboplatin 29.8, carmustine 37.0, nimustine 48.9, and lomustine 76.7. The most resistant cell was SNB56, followed with increasing sensitivity by SF128 and A172, and primary cultures P497, SF210, U87MG, SF126, 9L, P540, U251MG, HU62, C6. The complete list of original data is available upon request.
Conclusion: The efficacy of nitrosourea in vitro is low.