n-desmethyltamoxifen and Neoplasm-Metastasis

The steady-state pharmacokinetics of tamoxifen and its metabolites was studied in sixteen patients with advanced mammary cancer. Patients were randomized to receive tamoxifen given as Tamofen, Leiras, or as Nolvadex, ICI, 20 mg twice daily for 16 weeks in a cross-over study. Plasma and urine samples were analyzed during one dose interval (12 h) after treatment for 8 and 16 weeks. The concentrations of tamoxifen, N-desmethyltamoxifen, N,N-desdimethyltamoxifen, and metabolite Y were determined in plasma and the areas under the plasma level curves were calculated. 4-Hydroxytamoxifen was not found in plasma. In urine samples only tamoxifen and N-desmethyltamoxifen were above the detection limits even though metabolite Y was also analyzed after acid hydrolysis. There were no statistically significant differences in the concentrations of tamoxifen and its metabolites between the two preparations. The results of nonresponders did not differ from those of responders. Liver metastases had no effect on the metabolism of tamoxifen.

Topics: Aged; Breast Neoplasms; Clinical Trials as Topic; Female; Humans; Kinetics; Middle Aged; Neoplasm Metastasis; Random Allocation; Tamoxifen

Endocrine therapy for hormone-sensitive breast cancer is a well-established treatment option, both in adjuvant and palliative settings. For patients undergoing chronic hemodialysis, only scant pharmacokinetic data have been published for tamoxifen, and no data have been published for anastrozole. We therefore measured plasma levels of tamoxifen, its major metabolite, N-desmethyl tamoxifen, and anastrozole in a breast cancer patient undergoing chronic hemodialysis. Clinical tolerability was good. The blood levels for tamoxifen, N-desmethyl tamoxifen and anastrozole were within the expected therapeutic ranges. From this study, we can conclude that endocrine therapy for breast cancer with tamoxifen or anastrozole seems feasible and safe for patients undergoing chronic hemodialysis.

Topics: Anastrozole; Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Female; Humans; Middle Aged; Neoplasm Metastasis; Nitriles; Renal Dialysis; Tamoxifen; Triazoles

As previously reported, ovarian epithelial carcinomas may respond to endocrine therapy. We examined the direct effect of progesterone, medroxyprogesteroneacetate, gestoneron, 17-beta-estradiol, tamoxifen, 4-OH-tamoxifen, or N-desmethyltamoxifen on the proliferative capacity of ovarian carcinoma cells by means of the colony assay described by Hamburger and Salmon. The growth rate of 25 tested tumors (ascitic fluid, primary tumor, metastases) was 68%. The plating efficiency was 0.078%. Beside the drug testing estrogen and progesterone receptor levels were determined. The inhibition of colony survival was slightest with 17-beta-estradiol, more pronounced with medroxyprogesteroneacetate, gestoneron, N-desmethyltamoxifen, and progesterone, and greatest with 4-OH-tamoxifen and tamoxifen. Significant and dose-dependent inhibition of greater than 70% was observed with tamoxifen and 4-OH-tamoxifen in 80% of the tested tumors. There was no significant correlation between the in vitro responsiveness and the level of hormonal act not only via an estrogen receptor but also via an antiestrogen-binding site.

Topics: Adenocarcinoma; Aged; Cell Division; Cells, Cultured; Estradiol; Estrogen Antagonists; Ethanol; Female; Gestonorone Caproate; Humans; Medroxyprogesterone; Medroxyprogesterone Acetate; Middle Aged; Neoplasm Metastasis; Neoplastic Stem Cells; Ovarian Neoplasms; Progesterone; Receptors, Estrogen; Receptors, Progesterone; Tamoxifen