Dr. Sunil Singhal is the director of the Thoracic Surgery Research Laboratory at the Perelman School of Medicine at the University of Pennsylvania, a laboratory he started four years ago. He and a team of researchers last week secured a $7 million, five-year Transformative Research Project Award from the National Institute of Health for clinical trials of fluorescent nanoparticle probes that hone in on cancer cells with the goal of making the cells easier to identify from the surrounding tissues (particularly the edges of a tumor) and easier to remove surgically.
He believes the new technology, though far from commercialization, will change the way some cancers are removed.
Q. What are the current limitations to operating on cancer patients?
A. The biggest challenge is that for 20 years we’ve been doing surgery the same way. We do a CAT scan imaging study to see where the cancer is. Once we see the tumor on the CAT scan, we plan our operation. But we don’t have a CAT scan in the operating room. And then we use our hands and eyes to see where the tumor is. The problem is that it’s not 100 percent reliable.
For example, with breast cancer surgery, it’s not uncommon not to get all of it. In those cases there is a risk of a recurrence which the cancer would grow back and more aggressively than before. Therefore, women get radiation to their breast after surgery.
With any cancer we worry about the margins, especially brain cancer where you can’t take any more tissue than you absolutely have to.
Q: When was the technology developed?
A. We have been developing the technology for four years now. We started with mice and we have had a clinical trial at the School of Veterinary Medicine at the University of Pennsylvania on dogs with lung cancer and have a trial open with humans now.
Q: What’s used to highlight the cancer cells?
A: A nonradioactive dye —there’s no risk to the person. It is a chemical composition of nanoparticles and can be seen with an infrared imaging device. It is totally nontoxic. These are low energy devices — they have less energy than a lightbulb.
The basic idea seeks to accomplish three things: to get at the margins of the tumor, to make sure we get it all; see if the cancer has spread to the lymph nodes; and highlight any additional organs where there is cancer.
Q: How is the surgery done?
A: We would do a dose of the nanoparticles and then do the surgery the next day.
Q: What is the scope for this technology? In the announcement it focused on lung cancer.
A: I am a lung cancer surgeon so that’s what I do, but it would definitely be applicable to breast cancer, which is our next step, and then brain cancer. I think it will change the paradigm for cancer surgery — this is a totally new way for surgeons to approach cancer. This is applicable to all cancers that require surgery.
Q: How would the infra-red dye be seen?
A: We are still working on that. We have to use an infra-red camera to see the cancer cells, but they would be projected on a monitor. We’re still trying to develop software to project them onto a screen.