BSD Medical files patent for 'smart bomb' delivery of chemotherapy in breast tumors

Jun 19 2007

BSD Medical Corp. has filed a patent for a new non-invasive phased array breast treatment applicator developed to selectively heat breast cancer tumors.

This novel capability is uniquely applicable to the 915 MHz operating frequency of the BSD-500 hyperthermia system.

The company discovered through research that at 915 MHz the characteristics of breast tumors 4-5 centimeters in diameter (those typically treated with radiation and/or chemotherapy) selectively absorb microwave energy, while the microwaves largely pass through the other tissues of the breast. The discovery of this selective heating capability could be used in numerous ways for better delivery of hyperthermia in treating breast cancer. However, one of the novel applications is to use selective heating of breast tumors to release tiny heat-triggered capsules of chemotherapy drugs as they enter breast tumors through the blood stream, causing the capsules to burst inside the tumor, greatly multiplying the potency of the drug delivery. In this case the breast applicator would serve as the "targeting system" to find and heat tumors and the heat-triggered drug capsules would become "smart bombs" that release when heated as they enter the tumor.

Duke University is already using BSD Medical's hyperthermia equipment to release chemotherapy drugs delivered in heat-triggered capsules, and one of the reasons for this new applicator development was to further support Duke's research already underway. This method of providing chemotherapy thus far has shown the ability to deliver 30 times more drug than would normally reach the tumor site with non-encapsulated drug. In addition to releasing the chemotherapy capsules, heat (hyperthermia) therapy makes the tumor's blood vessels porous so that the capsules can pass from the bloodstream into the tumor. Hyperthermia also increases oxygen levels within tumors, and oxygen is critical to the proper functioning of certain chemotherapy agents. Hyperthermia also amplifies the level of genetic damage that chemotherapy inflicts on cells by inhibiting enzymes that normally repair the damage.

Breast cancer tumors that reach a diameter of 4 centimeters or larger are commonly treated by radical breast removal. An important objective of this effort is to provide less invasive alternatives for treatment.