By Mark Dwortzan
After diagnosing a patient with metastatic breast cancer, physicians routinely administer highly toxic chemotherapy drugs for months at a time, and then use an MRI or other imaging device to determine if tumors have shrunk or expanded. But changes in the size of a tumor may appear long after it becomes resistant to the administered drug. By the time such changes are detected and a new treatment regimen is applied, it may be too late to save the patient. The average survival time from diagnosis is just three years.
If physicians could detect when a patient’s metastatic tumors become resistant to treatment in real time, however, they could modify the drugs they’re administering in a timely manner. Assistant Professor Darren Roblyer (BME) has advanced a noninvasive, optical technique called diffuse optical spectroscopy (DOS) that’s designed to monitor tumor development and optimize drug selection in real time, and thus reduce drug resistance and potentially lethal side effects. A novel approach that’s already showing promise in early stage breast cancer treatment monitoring, DOS may ultimately help extend the lives of metastatic patients.
Impressed with the potential of the technique, theDOD Breast Cancer Research Program has selected Roblyer as one of four recipients of its 2014 Era of Hope Scholar Award, which recognizes outstanding early-career breast cancer researchers who have shown extraordinary creativity, vision, productivity and leadership potential. The five-year, $4 million grant will fund instrumentation development and preclinical and clinical studies for the DOS technique. The sole principal investigator on the project, Roblyer will collaborate with Professor Irving Bigio (BME); Professor David Waxman (Biology, Bioinformatics, MED); Associate Professor Rita Blanchard (MED), an oncologist at Boston Medical Center; and Harvard Medical School Associate Professor Sughra Raza, who specializes in radiology at Brigham and Women’s Hospital.
“It’s a pretty rare accomplishment for an assistant professor to lead a multi-investigator project of this scope,” said University of Utah Professor of Bioengineering John White, who begins serving as BME Department chair in May.
Wearable by the patient or handheld by a clinician, the tumor-tracking probe that Roblyer is developing transmits near-infrared light that penetrates deep inside cancer tissue. Some of the light is absorbed within cancer tumors and some is scattered back to a detector on the probe. Based on the probe’s continuous optical measurements of the absorption and scattering of light within a tumor, a clinician could determine rapid changes in the tumor’s structure and metabolism that indicate its resistance to current treatment. A new course of treatment could then be implemented.
Roblyer views his technique as analogous to those used to track HIV/AIDS patients’ responses to treatment.
“Over the past twenty years, researchers have developed more effective drug cocktails to treat patients with HIV/AIDS, and the ability to track the progression of the virus in the bloodstream so they could change the drug cocktail as needed,” he explained. “We want to do the same thing with cancer, using optical markers rather than blood markers to alert clinicians as to when it’s time to modify treatment.”
In the next five years, Roblyer aims to conduct several preclinical studies of the probe using mice as models of metastatic breast cancer, and then pursue a pilot human study involving about 30 patients. All studies funded by the grant will focus on monitoring lesions in the spine, one of the key sites to which metastasizing breast cancer spreads.
While initially focused on monitoring metastatic breast cancer, the DOS technique could be developed to address other cancers. Breast cancer was chosen as a starting point because the metastatic tissue involved is very transparent to light and the tumors are easier to access, as well as a significant demand for better treatments in this patient population.