Doxorubicin distribution in human breast cancer

Area of Science:

• Pharmacology
• Oncology
• Biochemistry

Background:

• Doxorubicin (DX) is a key chemotherapeutic agent for locally advanced breast cancer.
• Understanding its pharmacokinetic and tissue distribution is crucial for optimizing treatment efficacy and managing toxicity.

Purpose of the Study:

• To evaluate the plasma pharmacokinetics of doxorubicin (DX).
• To determine the tissue distribution of doxorubicin in patients with locally advanced breast cancer.

Main Methods:

• High-performance liquid chromatography with fluorimetric detection was used.
• Plasma and tissue (tumor, normal breast, lymph nodes, fat, skin, muscle) samples were analyzed at various time points post-injection (30 min, 24 hrs, 48 hrs).

Main Results:

• Doxorubicin plasma levels best fit a triexponential equation with a long elimination half-life (37.6 ± 4.9 hours).
• Tumor doxorubicin concentrations were significantly higher (55.2–337.4 times plasma levels at 48 hrs) and more sustained than plasma concentrations.
• Higher doxorubicin concentrations were observed in lymph nodes (normal and metastatic) compared to tumor, normal breast, fat, and skin.

Conclusions:

• Doxorubicin exhibits prolonged exposure in tumors and lymph nodes compared to plasma in breast cancer patients.
• Significant interindividual variability exists in tumor doxorubicin concentrations.
• These findings highlight the importance of tissue-specific drug accumulation in the therapeutic strategy for breast cancer.