Synergistic and tumour selective effects of chemotherapy and ultrasound treatment

In the present work, we have analysed the effects of low frequency ultrasound exposure in combination with liposomally encapsulated doxorubicin (Caelyx) and Plurogel encapsulated fluorouracil (5-FU) on 144 Balb/c nude mice inoculated with a WiDr (human colon cancer) tumour cell line, at various concentrations. Furthermore, the theoretical foundation for the effects of ultrasound exposure of tissues and organs, and for its interaction with and enhancement of controlled release of encapsulated anticancer drugs are outlined. For the first time, it is shown that non-hyperthermic ultrasound treatment significantly increases the effect of liposomally encapsulated cytostatic drugs on tumour growth. Synergetic effects were larger for low drug concentrations, indicating that the approach may benefit patients for whom chemotherapeutic treatment gives limited effect, or for whom drug concentrations have to be restricted due to general health considerations.