Pioneers in the Fight Against ‘the Big One’: Proton Therapy for Lung Cancer

Physicians at The University of Texas MD Anderson Proton Therapy Center are leaders in the research and treatment of lung cancer and pioneers in developing proton therapy for lung cancer patients. With its advanced image guidance and ability to precisely target tumors in the lungs, the powerful radiation of protons can be delivered with optimal accuracy – sparing critical nearby structures, such as the esophagus, heart and spinal cord. Because the tumor can be treated with a higher dose of radiation, benefits may include better local control of the disease, higher survival rates and improved quality of life.

“MD Anderson is at the forefront of the most advanced lung cancer treatments available. It is part of our mission to raise awareness of proton therapy as a potential option for people fighting for their lives,” says James D. Cox, M.D., former head of Radiation Oncology at MD Anderson. “When the Proton Therapy Center was established in 2006, for example, it was the first to treat lung cancer with protons and chemotherapy.”

Proton Therapy at MD AndersonRoughly 15 to 20 percent of lung cancer patients have tumors that can be treated with surgery combined with other therapies such as radiation. Another 30 to 50 percent of patients have locally advanced tumors that require a combined treatment regimen that includes chemo or targeted therapy in addition to radiation therapy. However, it is challenging to deliver an adequate dose of radiation to a cancerous tumor while sparing nearby normal tissues.

Proton therapy’s advantage for many lung cancer patients is based on this feature. Further, by minimizing the exposure of normal tissues, proton treatment may also reduce some of the side effects of traditional radiation and help patients maintain good quality of life.

Proton therapy is currently available at only 11 centers in North America (13 centers are in development). MD Anderson has one of the largest and most technically advanced centers in the world. The 96,000-square foot Proton Therapy Center – the first proton center in the world within a comprehensive cancer center – offers a range of proton treatment options. These include pencil beam proton therapy, a highly precise form of proton radiation also known as scanning beam, and intensity-modulated proton therapy (IMPT) – the most advanced form of proton radiation. For patients with recurrent lung cancer, who have already received full doses of traditional radiation, pencil beam and intensity-modulated therapies may further limit or eliminate radiation to sensitive areas.

The Proton Therapy Center treats as many as 900 patients annually. Nearly 5,000 patients have been treated to date, accounting for 15 percent of the total number of patients who have received proton treatment nationally. Approximately 1,000 of these patients have been treated for lung cancer. The best lung cancer candidates for proton radiation are those whose cancer is localized in the chest and can’t be removed surgically, notes Cox.

“We’re just beginning to see the potential benefits of proton therapy and as we move forward it looks more and more like an excellent treatment modality,” says Anne S. Tsao, M.D., associate professor in Thoracic/Head and Neck Medical Oncology. “As we learn more and gather evidence of these benefits, proton therapy will likely be extended to a broader patient population.”

“We’re just beginning to see the potential benefits of proton therapy and as we move forward it looks more and more like an excellent treatment modality,” says Anne S. Tsao, M.D., associate professor in Thoracic/Head and Neck Medical Oncology. “As we learn more and gather evidence of these benefits, proton therapy will likely be extended to a broader patient population.”

Research

The Proton Therapy Center is advancing the science of proton therapy by providing answers to critical knowledge gaps, confirming the effectiveness of proton therapy and evaluating its use in combination with chemotherapy, targeted molecular therapies and conventional radiation therapy.

Every patient treated at the Proton Therapy Center is offered the opportunity to participate in one of more than 25 clinical protocols, which allow for the capture, analysis and reporting on treatment results related to tissue toxicity, dose optimization, and quality of life.

Lung cancer patients, for example, may take part in a phase II randomized clinical trial comparing high-dose traditional intensity-modulated radiation therapy (IMRT) with high-dose proton therapy. MD Anderson researchers are also investigating such areas as long-term outcomes for patients with locally advanced lung cancer treated with proton therapy and survival rates among proton lung patients versus those treated with traditional radiation and chemotherapy.

Since 2005, MD Anderson has published more than 175 studies focused on proton therapy for lung cancer. Recent findings include:

• Concurrent chemoradiation therapy, the standard of care for locally advanced non-small-cell lung cancer (NSCLC), can cause esophagitis and pneumonia, and X-ray-based radiation often cannot be given at doses high enough to destroy tumor cells without toxicity to nearby normal tissues. In a study published in the journal Cancer, researchers showed that higher doses of proton radiation can be delivered to lung tumors with lower risk of these life-threatening conditions.
• Comparing toxicity and tumor coverage delivered to stage 1 NSCLC patients via traditional stereotactic body radiation therapy, passively scattered proton therapy and intensity-modulated proton therapy, researchers found that: the proton radiation approaches were better in terms of target volume coverage; significantly reduced the mean total lung dose; and reduced mean maximal dose to other nearby critical structures, including the aorta, heart, pulmonary vessels and spinal cord. The study was published in the International Journal of Radiation Oncology, Biology, Physics.
• Proton Therapy Center researchers have completed phase I of a study, published in the International Journal of Radiation Oncology, Biology, Physics, examining the effect of shorter courses of proton beam therapy in patients that have locally advanced NSCLC but that cannot receive chemotherapy with radiation. Using higher doses of proton beam therapy, treatment was typically completed in approximately three weeks.

“Advances are rapidly occurring in the field of proton therapy for lung cancer. Consider the ability to precisely target a tumor that moves with every breath or radiating a recurrent cancer that previously we wouldn’t have because of the toxic effects of earlier treatments,” says Daniel Gomez, M.D., assistant professor in Radiation Oncology. “Evidence-based innovations in proton therapy are making it possible to treat complicated tumors that traditional forms of radiation can’t target as effectively. As more patients are treated, the technology will continue to improve.”

Here are three lung cancer patients who credit proton therapy with saving their lives.

Chuck Martinez: From Cancer Survivor to Marathon RunnerIn 2007, just a year after surviving bladder cancer, 37-year-old Chuck Martinez began his fight against stage IIIA non-small-cell lung cancer.

“Chuck was the perfect candidate for proton therapy,” says his physician, Ritsuko Komaki, M.D., director of MD Anderson’s Thoracic Radiation Program. “With the location of his tumor, it was critical to limit the radiation dose to surrounding areas, especially since he was on concurrent chemotherapy.”

Cancer-free since 2010, Chuck still wonders what may have caused his lung cancer. “I’ve never been a smoker, so it has been one of the big mysteries for me.”

“For reasons not fully understood, lung cancer is becoming more frequent in young, healthy individuals,” says Joe Y. Chang, M.D., Ph.D., professor and clinical section chief of thoracic radiation oncology. “In their 30s and 40s, these patients hopefully have long lives ahead and every effort must be made to provide a treatment option that will help assure those years are spent with good quality of life.”

Today, Chuck is dedicated to a healthy lifestyle. He lost 30 pounds and has completed five half-marathons. He recently completed the 2013 Chevron Half Marathon in Houston, finishing in two hours and five minutes. “Running marathons never crossed my mind. My wife and I used to watch them every year on TV, wondering ‘What does it take for someone to do that?’ I never thought it would be me,” he says.

Suzan Shughart: Not Taking ‘No’ For an AnswerWhen Suzan was told she had no more than two years to live at age 59, she refused to accept a death sentence. A routine checkup had resulted in the discovery of a large tumor in the middle of her chest, but she says, “I didn’t panic. I remember thinking, calmly, ‘Oh, so this is how it happens, this is how I die.’ And then immediately deciding I would beat this.”

Her determination led her to MD Anderson, where doctors agreed that she didn’t have to accept the prognosis. After the tumor was surgically removed, Suzan returned home to Scottsdale for chemotherapy. But five months later, the cancer came back. She decided to return to MD Anderson, where proton therapy was recommended.

On her 60th birthday Suzan rang the Proton Therapy Center’s ceremonial gong, marking the end of her treatment. “I never felt sick. I drove myself to proton therapy every day and used my time in Houston to explore and spend time with my son, daughter-in-law and baby granddaughter.”

Today, seven years after her first diagnosis and also after undergoing treatment at MD Anderson for breast cancer, Suzan is in remission. She’s thankful for the care she’s been given, but also for having the courage to take charge of her health and find the best solution.

Billy Walls: The World’s First Lung Cancer Patient Treated with Pencil BeamAlways active, Billy Walls served 20 years in the Army before transitioning to an electronics career in El Paso. He was enjoying an active second retirement working with Habitat for Humanity when, in 2004, he started coughing up blood.

Diagnosed with lung cancer, Billy underwent surgery, chemotherapy and traditional radiation. Then in 2008, he began coughing up blood again. Though checkups showed no signs of cancer, the symptoms resurfaced and in 2010 doctors confirmed the cancer’s recurrence. Billy came to MD Anderson, where he became the first person in the world to receive pencil beam proton therapy.

“My physician – Dr. Chang – told me that receiving radiation twice for the same cancer is extremely rare – and that because of my previous levels of radiation exposure, pencil beam would be the best treatment,” he says. He received 33 treatments over a two-month span while also undergoing chemotherapy.

“It was imperative to target Billy’s tumor with the greatest amount of accuracy while limiting exposure to parts of his lung that had previously received radiation,” says Chang. “With pencil beam technology, we were able to conform the treatment to the exact shape and depth of the tumor and deliver the highest dose of radiation possible.”

Before pencil beam, reradiating Billy’s lung would have been impossible. To date, MD Anderson has treated about 30 similar cases.

Now 78 years old, Billy is enjoying his life at home with his wife.