Using a technique called PCR (polymerase chain reaction) to measure tumor DNA, they found that, on average, 90 percent fewer cancer cells remained after surgery to remove tumors in mice using the probe-based molecular guidance compared to surgery without it - a 10-fold reduction. They also found that the fluorescently labeled probes hit their mark 93 percent of the time, allowing the researchers to "see" left over tumor tissue.

According to the scientists, only a single injection of the nanoparticle-based probe containing the fluorescent and magnetic tags was needed in order to use MRI to examine the entire mouse model for tumors before and after surgery, in addition to the real-time guidance in surgery.

Nguyen said that in the future, additional tags may be added, and eventually, a cocktail of personalized probes may be designed for individual types of cancers. If the nanoparticle-based probes are successful in finding tumor cells in humans, the researchers envision using them eventually to deliver chemotherapy drugs to finish off the remaining cancer.

Tsien and Nguyen see many advantages to molecularly guided cancer surgery. Probes can be useful in staging cancer, particularly in prostate cancer, and can be used in a variety of tumor types. In addition, such biological probes can be used in laparoscopic and robotic surgery, where surgeons cannot feel the tumor, and rely much more on sight. If surgeons can completely remove a cancer, it may mean a patient could be cured quickly, and at relatively low cost when compared to long-term chemotherapy.

Source: University of California - San Diego