[Predictive tumor tests in chemotherapeutic treatment concepts of malignant diseases]

In order to determine the pre-therapeutical effectiveness of cytotoxic drugs in metastasizing tumours, two in vitro test methods were examined for their predictive validity: the short-term incubation of tumour cells with cytotoxic drugs and radioactive labelled precursors of the DNA- or RNA-synthesis, and the testing of the cloning ability of tumour cells, pre-incubated with cytotoxic drugs. The short-term incubation techniques were directed in two directions: the testing of sensitivity and the testing of resistance. Both methods can only be carried out using strong proliferating tumours. With methodical, pharmalogical and biological problems, the sensitivity test results in a relatively minor correlation between the in vitro and in vivo reactions. Contrary to this the resistance test allows a predictive, clinically utilizable judgement of primary and secondary forms of the tumour-cell resistance of specific cytotoxic drugs. The consecutive measurement of the proliferative activity of tumours before and after a systematic chemotherapy also seems to be an able parameter concerning the clinically expected effectiveness of cytotoxic drugs. Compared to the other in vitro tests the tumour-cell clonogenic assay demonstrates two main advantages: firstly, all cytotoxic drugs can be analysed by this test method, and secondly, little proliferating tumours can also examined. Nevertheless, this test method seems to be more suitable for predicting tumour-cell resistance than the sensitivity of cytotoxic drugs.