Monitoring of Breast Tumor Response to Local Chemotherapeutic Agent Delivered by Biodegradable Fibers

摘要

For the third year of the project, we have investigated the radiotherapy effects on rat breast tumor hemodynamics and also analyzed our previous data obtained from chemotherapy study with our mathematical model, which showed very good correlations between the hemodynamic parameters and tumor responses to the therapy. For experiments, we have applied single dose of radiation (30 Gy) to two groups of rats bearing syngeneic 13762NF mammary adenocarcinomas: one group received a radiation therapy during air inhalation and the other group was treated by irradiation during oxygen inhalation. Acute effects were not observed during irradiation, but significant changes in vascular hemodynamic response to oxygen inhalation were observed from both groups at day 1 after irradiation. The preliminary results suggest that tumor oxygenation during radiation therapy may play a great role in treating the tumor. We have further analyzed our previous data from tumors treated by chemotherapy using our bi-exponential model. In cyclophosphamide study, maximum changes of oxyhemoglobin and amplitude of fast component from the fitting after cyclophosphamide treatment showed a good correlation with the tumor volume regression. From combretastatin A4 phosphate (CA4P) study, the changes of fitted parameters before, during, and post administration of CA4P treatment showed very similar results from previous studies. All the results again strongly support that near infrared spectroscopy with our model can be used to monitor the therapeutic responses of tumors after treatments. This will also be a great help for physicians to decide the direction of each patient's treatment, which will enhance the survival rate and reduce side effects.