[Problems in chemosensitivity testing].

Although chemotherapy is promising as one form of treatment within its field, its therapeutic benefit has yet to be fully utilized because drug sensitivity tests have not been sufficiently used as predictors of response. The currently available prediction accuracy of drug effectiveness is said to be in the range of 60-69%, while the prediction of their ineffectiveness is reportedly 91-97%. The elimination of ineffective drugs is an issue of crucial importance because the side effects of carcinostatic agents are severe. It has been argued that in vivo effects cannot be accurately predicted on the basis of in vitro results for a variety of reasons. There are the roles played by the route of administration, intra-cellular distribution and clearance. In addition, there are also the roles of pharmacokinetics, structural factors related to spheroidal tumors, variations of the micro-cellular environment and so forth in the in vivo situation. To date, a short-time clinical usefulness of sensitivity tests has been reported, but whether there is predictive value for longer-term survival remains to be elucidated.