Implantable device for advance testing.

• Position: Cancer Drug

More than 100 drugs have been approved to treat cancer, but predicting which ones will help a particular patient is an inexact science at best. A device developed at the Massachusetts Institute of Technology, Cambridge, may change that.

Implantable, and about the size of a grain of rice, it can carry small doses of up to 30 different drugs. After implanting it in a tumor and letting the drugs diffuse into the tissue, researchers can measure how effectively each one kills the patient's cancer cells. Such a technique could eliminate much of the guesswork now involved in choosing cancer treatments, says Oliver Jonas, a postdoctoral student at MIT's Institute for Integrative Cancer Research and lead author of a paper describing the device in Science Translational Medicine.

Most of the commonly used cancer drugs work by damaging DNA or otherwise interfering with cell function. Recently, scientists have developed more-targeted drugs designed to kill tumor cells that carry a specific genetic mutation. However, it usually is difficult to predict whether a particular drug will be effective in an individual patient.

In some cases, doctors extract tumor cells, grow them in a lab dish, and treat them with different drugs to see which ones are most effective. However, this process removes the cells from their...