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Expanding Proton Therapy's Benefit

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MD Anderson Physicians Work to Improve Patient Options with Proton Therapy 

The first decade of the 21st century has seen proton therapy go from an obscure “alternative” radiation treatment to a technology with the potential to assist an ever-growing number of cancer patients as techniques and applications advance and expand. Currently, there are nine operating facilities in the U.S., another four under construction or development and several more in the planning stages. In a rapidly growing industry, MD Anderson’s Proton Therapy Center and its dedicated physicians and staff have contributed significantly to progress in the field and strive daily to improve patient care and comfort both from the direct optimization of proton therapy, as well as advances in conventional radiation therapy techniques, which could be employed in places without access to proton therapy.

Youth may be when most physicians are formed, at least if you take Joe Y. Chang, Ph.D., M.D. and Andrew K. Lee, M.D., MPH as examples. Both are faculty members in MD Anderson’s Radiation Oncology Department, both are intent on improving patient care with proton therapy and both had inspiring influences at an early age, shaping not only their desire to become physicians, but the type of result-oriented researchers they are today.

Associate Professor Chang remembers being in high school when his father was diagnosed with tuberculosis.

“At the time I had no idea how to become a doctor, but I knew I wanted to help people like my father and their families, who also suffered,” explains Chang. “So after that, everything about school was about going to Medical School.”

And so he did, ultimately attending Fudan University Shanghai Medical College, an institution with which he continues to maintain close ties. Eventually, Chang focused on Radiation Oncology as a way to directly benefit patient’s by working to improve the application of technology to affect disease and improve outcomes.  

Lee, the Director of MD Anderson’s Proton Therapy Center, also spent the better part of his youth knowing he would attend medical school, although the precise moment of decision is lost. Perhaps, it was always there, as Lee’s mother, Chung K. Lee, M.D., who is a full professor in the Department of Therapeutic Radiology-Radiation Oncology at the University of Minnesota, shaped his life by example. Although Lee admits taking from his mother the goal of becoming a physician, even he did not think he would focus on Radiation Oncology as a specialty.

“I was always interested in science, but I wanted my science to be applicable and able to affect people’s lives,” Lee recounts. “As I did rotations in medical school I realized Radiation Oncology was a good fit for me because you had to work on the science, but it was science that mattered to the patients.”

Both Chang and Lee now work in the relatively nascent field of proton therapy, which to those who are unfamiliar with its employment in cancer treatment, is the use of protons for radiation treatment as opposed to conventional X-rays. Protons can be energized to a precise level so they deposit the majority of energy at one “programmed” location. Going through the human body, this means they minimize radiation exposure to tissue physicians do not want to affect, and release a higher dose of radiation to the chosen site with no exposure beyond that point. This is not possible with photon radiation. In short, less damage, more treatment.

Initially proton therapy focused on treating very precise forms of cancer, with prostate being the most widely treated. With advances in technology, however, Chang and Lee consistently voice two objectives in their work: to broaden the use of proton therapy to treat additional types of cancer and to increase proton therapy’s effectiveness. That effectiveness comes in the form of not only killing cancer, but being used in concert with other treatments to improve patient’s ability to tolerate the entire suite of tools used for treatment.

A recently completed research study led by Chang entitled Phase 2 study of high-dose proton therapy with concurrent chemotherapy for unresectable stage III nonsmall cell lung cancer, showed a decrease in the local recurrence of tumors from 50% with conventional radiation therapy to 20% with proton therapy, increased life-expectancy and reduced toxicity from the concomitant chemotherapy. Patients were able to handle the effects of chemotherapy better with higher proton therapy doses than if the chemotherapy was used with lower doses of conventional radiation therapy.

Lee explains that improving the ability of proton therapy to eliminate an even greater percentage of tumors lies in advancing techniques such as pencil beam, or spot scanning. As opposed to conventional passive-scattered proton therapy, pencil beam technology allows radiation oncologists to pinpoint their target and conform the radiation dose more precisely to the shape of the tumor. MD Anderson was the first location in North America to treat patients with pencil beam scanning and as a result treats a wider range of tumor sites with proton therapy, such as brain, head and neck, thoracic and esophageal.

As wonderful as the prospects are for proton therapy, everyone in the world does not have access to the technology. For that reason, researchers like Chang continue to work to optimize more widely used technologies to assist patients. In one case, those efforts are in collaboration with MD Anderson Sister Institution, Fudan University Cancer Hospital. Their Randomized study to compare Stereotactic Ablative Radiotherapy vs. Surgery in operable or marginally operable peripheral stage Ia Non-Small Cell Lung Cancer recently received $600,000 of support from Varian, Inc. The goal of the study is to determine if image-guided Stereotactic Ablative Radiotherapy using photons can improve the survival for patients with NSCLC. Stereotactic Ablative Radiotherapy in lung cancer using protons may further improve the toxicity and has been actively studied at MD Anderson.

With improvements in both conventional and proton therapy radiation treatments, advances in technology and a broader use of improved techniques and new technologies, both Chang and Lee are optimistic about patient’s prospects when choosing how to confront cancer.

“In Asia alone, they are discussing developing five proton therapy centers,” explains Chang. “The more people who are interested in the technology, the more technological innovations will occur.”

Lee seconds the sentiment, “Eventually, we will reach a critical mass of proton therapy facilities and researchers advocating its use,” says Lee. “This will dramatically improve technology and techniques associated with proton therapy, which ultimately will help us minimize the side effects to, and improve the care of, patients.”

© 2015 The University of Texas MD Anderson Cancer Center