Q&A Topic: Increasing Use of Combined Modality Treatment to Treat Cancer
Henry Lee, MD, PhD
Q: What inspires you about the work you get to do?
A: After developing neurosurgical and pharmacologic therapies, I decided to focus on radiation oncology because my advances in this field were implemented into patient care within months rather than years. There’s a real, tangible sense of progress in this field. These advances include technologies that have now become commonplace methods of treating patients with radiation therapy, technologies such as intensity-modulated radiation therapy (IMRT) and stereotactic body radiosurgery (SBRT). Much of my work at NewYork-Presbyterian Lawrence Hospital now combines these advanced radiation treatments with chemotherapy to make chemoradiation a safer, more effective way of treating most types of cancer in the 21st century.
In retrospect, I’ve come to realize that these technologies were adopted quickly because they focused on increasing safety as the key to improving the efficacy of therapy. In radiation oncology, we embrace change, but carefully. First and foremost, we ensure that treatments are safe; then we make them more effective over time.
Q: How does radiation treatment for cancer basically work, and how do you combine it with other strategies?
A: Radiation oncologists use radiant waves of energy to treat all types of cancer (hence the term, “radiation therapy”). These radiant energy waves are essentially modified waves of light and thus are not radioactive. Instead of a lamp, we harness the quiet power of a linear accelerator (LINAC) to deliver our radiation therapy to treat cancers deep within the body or on the surface of the skin.
Radiation therapy from a radiation oncologist is a perfect complement to surgery from a surgical oncologist and the chemotherapy of a medical oncologist. Like surgery, radiation therapy is a precise local therapy: I can aim my beams of radiation with millimeter precision. Like chemotherapy, radiation therapy kills cancer cells by damaging their DNA in small doses, done daily, for as long as a few days to weeks. This cumulative assault kills cancer cells by damaging them beyond the point of repair. We keep the daily dose low enough so that normal cells can recover overnight. By the way, radiation oncologists are not radiologists. Whereas radiologists look for cancer, we are one of the three types of oncologists who use their own specialized tools to treat cancer.
We can enhance radiation therapy by combining it with a second modality at the same time—usually chemo. At a low dose, chemotherapy can make cancer cells more sensitive to the energy waves of radiation therapy. This approach is now routinely used on a variety of cancers, including head and neck cancer, lung cancer, esophageal cancer, and colorectal cancer. Many of these patients will be cured with chemoradiation and never require surgery. Approximately one-third of all radiation patients get combined modality therapy.
Q: What actually happens during combined modality treatment?
A: Those who qualify are typically in the middle group of patients. They don’t have early stage cancer, but they also (hopefully) don’t have cancer that has spread too far from the primary disease site. Depending on the situation, we may treat just the disease site or the disease site and the lymph nodes, in case we’re worried about the spread.
Before radiation therapy begins, each patient undergoes a highly specialized CT to create a map of the tumor target and the normal tissues around the tumor (the “simulation”). Then with the help of our physics team and computers, we spend several days to create and model a 3-D plan that uses a LINAC to deliver the patient’s radiation therapy (“treatment planning”). Each treatment plan is unique and tailored. When the patient is on the LINAC, the machine that actually treats the cancer not only delivers beams of radiation therapy, but also performs a CT scan immediately before treatment. This low-dose CT helps us aim the beam with a level of precision measured in millimeters to minimize damage to healthy tissue while ensuring that the tumor target is treated.
Q: What new ideas or technologies in your field get you excited?
A: The “next big thing” in radiation therapy involves combining radiation with the new generation of chemotherapy drugs: the immunotherapy agents. This process has the potential not only to hit the tumor directly but also to harness the body’s immune system to treat cancer far from the site. After all, radiation is a very potent stimulator of the immune system. And when combined with immunotherapy, this enhancement is taken to a whole new level. Researchers have gotten occasional good results in clinic, and trials are underway to figure out how to succeed more regularly and predictably.
Q: What misconceptions, if any, would you like to correct?
A: When doctors recommend combined modality therapy to patients, that’s not bad news! And it’s not a sign that the disease is worse than your doctors thought. What it means is that there’s an opportunity for you that others may not have—a chance that very well may make the difference and help you get across the finish line to achieve a cure.
NewYork- Presbyterian Lawrence Hospital Cancer Center
55 Palmer Avenue
Bronxville, NY 10708