Anthracycline-Resistant Breast Cancer

Oxidative stress induced in rat liver by anticancer drugs doxorubicin, paclitaxel and docetaxel

PURPOSE

Oxidative stress generated by anticancer drugs in non-targeted tissues, is considered as a significant factor responsible for their severe side effects, e.g. cardiotoxicity, neurotoxicity and hepatotoxicity. Lack of data on the effect of concurrent administration of commonly used anticancer drugs: doxorubicin (DOX), paclitaxel (PTX) and docetaxel (DTX) on normal tissue, prompted us to examine the markers of oxidative stress in the liver of rats treated with these drugs.

MATERIAL/METHODS

Male Wistar rats of average weight 200 g were injected intraperitoneally (i.p.) with 10 mg/kg of body weight (b.w.) of DOX, PTX and DTX. The drugs were given alone or in combinations DOX+taxane. The activities of superoxide dismutase (SOD), catalase (CAT), low molecular weight and total thiols and thiobarbituric acid-reactive substances (TBARS) were estimated.

RESULTS

Combination of two drugs generated greater changes than single agents. Concurrent administration of DOX and PTX increased SOD activity and TBARS, decreased the amount of low molecular weight and total thiols, but did not cause any changes in the activity of catalase. Combination of DOX and DTX induced similar changes except for the activity of catalase, which decreased after the treatment. Of the three drugs only DTX significantly decreased the activity of SOD. However, both taxanes increased the activity of catalase. Although a decrease in concentration of -SH groups, depletion of glutathione and an increase of TBARS were observed after treatment with single drugs, the changes were not statistically significant.

CONCLUSION

Concurrent administration of DOX and taxane induced enhanced oxidative stress in comparison to single drugs, which suggests their synergistic prooxidant mode of action in liver.

Monotherapy with paclitaxel as third-line chemotherapy against anthracycline-pretreated and docetaxel-refractory metastatic breast cancer

We describe a patient with anthracycline-pretreated and docetaxel-refractory metastatic breast cancer who achieved a complete response after third-line chemotherapy with paclitaxel. A 59-year-old woman underwent modified radical mastectomy for advanced cancer in her left breast after local arterial neoadjuvant chemotherapy with anthracycline. Postoperatively anthracycline-containing adjuvant therapy was administered. Pulmonary metastases occurred 15 months after surgery, which did not respond to 4 cycles of second-line chemotherapy with docetaxel, given at 60 mg/m(2) every 3 weeks. Therefore 210 mg/m(2) of paclitaxel was given every 3 weeks as third-line monotherapy and induced a complete response with grade 3 neutropenia and hair loss as the major adverse effects. We suggest that paclitaxel is potentially effective as third-line monotherapy for anthracycline-resistant and docetaxel-refractory metastatic breast cancer.