How Advances in Radiation Therapy Are Improving Care For Brain and Spine Tumors

December 20, 2019, by Brittany Cordeiro, NCI-CONNECT Program Manager

Radiation oncologist Christina Tsien, M.D., learned at a young age the impact of radiation therapy, a type of cancer treatment that uses beams of intense energy to kill cancer cells. At age 19, she was diagnosed with a rare sarcoma. After multiple surgeries and recurrences, she received radiation treatments that ultimately stopped her cancer from returning.

Now, as a physician, the experience of being a cancer patient has been an important part of her career. “I learned firsthand the impact of radiation therapy on curing cancer. Later, I gained insight into the impact of cancer care on longterm survivorship—and it is this understanding that now shapes many of the treatment decisions I recommend,” says Dr. Tsien, medical director of the Johns Hopkins Proton Therapy Center at Sibley Memorial Hospital in Washington, D.C.

Dr. Tsien received her medical degree from McGill University’s Faculty of Medicine in Montreal. She completed a radiation oncology residency and fellowship, then became a professor at the University of Michigan. In 2014, she joined the radiation oncology department at Washington University in St. Louis where she served as chief of the central nervous system service, director of clinical research, and co-medical director of stereotactic radiosurgery and the gamma knife center. In October 2019, she joined John Hopkins Medicine.

“We are now able to cure many types of cancer, but this often requires multiple types of therapies such as surgery, radiation, and systemic therapy. It is important that we, as cancer specialists, organize ourselves as teams to practice multidisciplinary medicine,” Dr. Tsien says.

Over half of all cancer patients will receive some form of radiation treatment. For people with rare brain and spine tumors, radiation treatment is often ideal because of its precision in targeting areas of the brain that are otherwise difficult to access. Proton beam therapy kills cancer cells by causing DNA damage while minimizing damage to the surrounding healthy tissue. Cancer cells whose DNA is damaged beyond repair stop dividing or die.

Understanding Proton Therapy Benefits  

Proton therapy is a type of advanced radiation technology. It takes advantage of a remarkable and unique characteristic of high energy particle beams and how they deposit ionizing radiation as they move through tissue. Unlike conventional gamma or X-ray beams, which do not stop as they pass through the body, the depth of proton therapy beams can be controlled. As the charged particles come to a stop, all their energy is deposited within the tumor with little to no exit dose to the surrounding tissues.

The most advanced type of proton therapy delivery is pencil beam scanning technology. Pencil beam technology allows for “dose painting” with a precise proton beam only a few millimeters wide to target the unique shape of individual tumors.

Radiation therapy that treats the brain and spine is called craniospinal radiation. This form of radiation may be used for rare tumors, including medulloblastomas, germ cell tumors, pineal region tumors, and other rare tumors.

“Patients are living longer than ever following a cancer diagnosis. The goal now is to find ways to lower the risk of treatment-related side effects, some of which do not become apparent until long after treatment has ended. Proton therapy can help achieve these goals,” Dr. Tsien says.  

With the precision of proton therapy, radiation oncologists are better able to minimize the longterm impact of radiation treatment on cognition, vision, hearing, and brainstem and endocrine function. “Proton therapy can often better integrate with other kinds of treatments and allow completion of more treatment cycles with less harm to patients,” Dr. Tsien says.

Proton therapy is not recommended in all clinical situations, and patients can often benefit from other types of highly conformal radiotherapy. “Focal treatments like stereotactic radiosurgery using photon radiation are exceptionally precise and effective,” Dr. Tsien says. “Each patient’s disease is unique. We aim to understand the individual as well as the disease, so we can provide a personalized treatment plan.”

Researching Radiation Effects and New Techniques  

Dr. Tsien’s research focuses on understanding the implications of proton therapy to achieve better outcomes. “Technology has allowed us to do things we could not do before. Advanced imaging techniques allow us to monitor treatment changes in real time and adapt radiotherapy treatment plans,” Dr. Tsien says. Additional tools like optical surface imaging and real-time fluoroscopic gating improve the precision of proton therapy and limit the movement of organs during treatment.

She is also developing novel methods to increase the therapeutic effectiveness of proton therapy. “We need to understand the effects of radiation on the tumor and its surrounding environment, as well as its effect on normal tissues, to find ways to improve effectiveness of novel therapies, including immunotherapy,” Dr. Tsien explains.

Dr. Tsien’s research involves advanced neuroimaging to improve image guidance and better direct how to safely increase the strength of radiotherapy in high grade gliomas to improve its effect. She studies biomarkers to predict a patient’s response to proton treatment. “Understanding a patient’s response to treatment earlier—whether it’s working or not—can be used to better predict patient outcomes,” Dr. Tsien says. 

To further move the neuro-oncology field forward, Dr. Tsien is working across disciplines and institutions. “We need to design innovative clinical trials incorporating novel translational science and hypothesis-driven clinical trials based on strong preclinical science,” she says.

Dr. Tsien is collaborating with the NCI Center for Cancer Research's Neuro-Oncology Branch to refer patients to its Natural History Study, which collects and analyzes tissue to discover mutations and learn more about each type of rare brain and spine tumor.

Valuing the Patient Perspective

Learning from her personal cancer experience, Dr. Tsien goes to great lengths to ensure the patient is considered in every treatment decision. “I aim to understand their personal situations and goals. This helps me shape their treatment plan and share it with them,” Dr. Tsien says.

“Patients need to understand their options and the risks and benefits, so they are very informed and can make decisions that are best for them. It is important to take the time to get to know the patient and their families and help them choose a treatment plan that is right for them, whether it is at our center or closer to their home,” Dr. Tsien says.

Her personal experience has made her more understanding of the decision process. “Radiation can be scary and overwhelming at first, but a physician can help coach families through it. A key part of the cancer care is encouraging patients and caregivers to ask questions and to be candid with their care team about their needs and aims,” Dr. Tsien says. “I often call on my experience as a cancer survivor. It has given me a better perspective of the important relationship between a physician and a patient.”