LIPID PEROXIDES IN THE POLYCHEMOTHERAPY OF CANCER-PATIENTS

There is evidence that a variety of anticancer drugs exert their cytot oxic activity by a free-radical-mediated mechanism. These drugs includ e anthracyclines such as adriamycin, daunorubicin, 4-epi-adriblastin a s well as bleomycin, procarbazine, vincristin, cyclophosphamide, etopo side and mitomycin C. The aim of this study was to investigate whether cancer patients who underwent polychemotherapy (n = 44) show more sig ns of oxidative stress in plasma than a group of healthy controls (n = 52). As an index of free radical generation, plasma concentrations of thiobarbituric-acid-reactive substances (TBARS), well-accepted as mar kers for oxidative stress, were determined by fluorometric detection a fter separation by high-performance liquid chromatography. In 12 cases , the TBARS were measured both before and after a chemotherapy course. After chemotherapy, 10 of 12 patients showed a marked increase in pla sma TBARS concentration compared to values measured before therapy [9. 02+/-1.84 nmol/ml (n = 12) vs. 11.58+/-2.49 nmol/ml (n = 12); p = 0.00 2, t-test for paired observations]. Tumor patients in general had sign ificantly larger amounts of TBARS in plasma in comparison with a contr ol group [mean 11.88+/-3.51 nmol/ml (n = 44) vs. 7.51+/-2.14 nmol/ml ( n = 52); p < 0.001, t test]. Our results are evidence that repetitive polychemotherapy with radical-generating compounds may exceed the anti oxidative capacities of cancer patients and may lead to oxidative stre ss.