The Cancer Fight, from Hiroshima to Houston
Dr. Ritsuko Komaki was living with her family near Osaka when the atomic bomb exploded on her native Hiroshima in 1945. But the family returned to the devastated city when she was four, and Komaki grew up a witness to the long-term effects, which likely contributed heavily to the deaths of about half her relatives, including her father. Like many Japanese, she developed both a fascination with and fear of radiation. When her close friend Sadako Sasaki died at age 11 of radiation-related leukemia, Komaki vowed to become a cancer doctor.
Today, Dr. Komaki has learned how to apply radiation creatively and no longer fears it; instead, as clinical section chief and program director of thoracic radiation oncology at The University of Texas M. D. Anderson Cancer Center in Houston, she uses it in increasingly sophisticated ways to fight cancer. She's one of the world's leading researchers and advocates of proton radiation beam therapy, an emerging treatment that many oncologists consider the safest and most effective available. And according to Komaki, her work is much better done in the context of a university program than at private institutions.
"Our patients, including all of our proton patients, are treated under clinical trials," which monitor results on large numbers of patients, she points out. "It's difficult to treat patients on trials at private hospitals or clinics. They don't have enough manpower, and they don't have review boards that can check on compliance of eligibility and maintain strict quality control of treatment. This means patients get better care here." Recently awarded the Juan A. del Regato Foundation Gold Medal for best educator and teacher, the higher education setting also allows Dr. Komaki to share her knowledge with future innovators. "I try always to educate younger people — students and trainees, as well as patients — to live healthy lives and achieve their goal to help others."
What is Proton Therapy?
Proton therapy, like other forms of radiation, aims ionizing particles (in this case, protons) onto a target tumor to damage and ultimately destroy its cancerous cells. But proton beams are much more localized and powerful than the X-rays used in more established radiation therapies. In the latter, the dosage is big enough to kill the cancerous cells, but some radiation also hits the healthy cells around the tumor. This can cause such side effects as pneumonitis, esophagitis and bone marrow toxicity, or lead to the growth of secondary cancers.
To reduce damage to healthy tissues by a scattered dose of low radiation, the oncologist requires sharply delineated radiation, and proton beams are shaped to almost perfectly match the specific tumor and aimed to strike it precisely. Collateral damage is thus minimal, making it feasible to hit the cancer with much bigger doses. In addition, photons (X-rays) release up to 90 percent of their cancer-fighting energy as they penetrate the skin, and lose 30 percent of it by the time they reach the tumor, meaning their overall effectiveness is reduced by 40 percent; they also exit out the rear of the tumor to further damage healthy tissues behind it. By controlling the speed with which it's shot into the body, the proton beam is calibrated to be at 30 percent of its maximum efficacy near the skin level while gathering full strength when it actually reaches the tumor and it barely exits the body at all.
Komaki says the treatment is most recommended for those whose localized cancer has not spread to distant parts of the body. The success rate against prostate cancer, for example, is around 90 to 95 percent. But proton therapy succeeds against many of the 130 known forms of cancer. A recent study led by Komaki and her husband Dr. James Cox, head of the division of radiation oncology at UT M. D Anderson Cancer Center, shows that proton therapy, when used simultaneously with chemotherapy to treat lung cancer, causes significantly less damage to surrounding healthy cells than other forms of radiation. It's also particularly effective for children, because it causes little, if any, collateral damage to their still-growing tissues and organs. Likewise, the elderly are strong candidates because tissues and organs surrounding their tumors are often too weak to withstand the more commonly employed radiation treatments. Dr. Komaki also stresses that the side effects are minimal, noting one patient who played a round of golf following each of his daily outpatient treatments.
"Patients think this is fabulous," she says. "You know why? They rarely get sick from proton treatment itself! 'Are you sure you're giving me the treatment?' they ask. It's amazing how much proton treatment they can tolerate compared to photon treatment."
Making Proton Therapy Accessible
When she entered medical school in Hiroshima, Komaki was taught that surgery was the only viable cancer cure. But in the 1970s — while doing her externship, internship, residency and fellowship in Milwaukee — she began learning "how radiation could cure people, and that gave it a different meaning to me than just the atomic bomb," she says. She came to view localized radiation treatment as less harmful than chemotherapy, and realized that it couldn't be equated at all with the scattered, uncontrolled radiation to the whole body that comes with exposure to an atomic bomb. In 1985, she and Cox went to Columbia Presbyterian Medical Center in New York to work with Dr. Eric Hall, then a leading international authority on the effects of the atomic bomb on humans. In 1988, she began putting her years of research to work at UT M. D. Anderson.
Though protons were discovered by Ernest Rutherford in 1919, proton therapy didn't commence until 1954, at Berkeley nuclear physics labs. The Harvard Cyclotron Laboratory partnered with Massachusetts General Hospital to begin treating cancer patients in 1961. But the necessary technology is so expensive that treatment remained confined to physics research labs until 1990. That's when the Proton Treatment Center opened at Loma Linda University Medical Center in southern California to offer the first hospital-based program.
Intrigued by the proton therapy research then available, Komaki and Cox visited Loma Linda early on, and began to push for a similar unit at UT M. D. Anderson when they returned to Houston. Their efforts paid off in 2006, when the $125 million Proton Therapy Center opened its doors offering a complete range of proton treatments. It's the only such facility in the Southwest. (In addition to Houston and Loma Linda, the nation now has centers in Florida, Indiana and Massachusetts, with several more being planned.) Today, Komaki and her colleagues treat thoracic malignancies — therapy that requires a team of seven doctors, several physicians and dosimetrists and a couple dozen technicians — in 10 to 15 patients daily, with four of them taking proton therapy. Like other radiation treatments, proton therapy runs about seven weeks. In all, the Proton Therapy Center, with Dr. Andrew Lee as medical director, treats 75 to 80 patients daily.
To Komaki, this is just the beginning. "Our physicists have already made a machine here that creates a scanning beam," she says. "We're the only place in the world with a scanning beam, which means we can remove neutron contamination." (Neutrons are created when protons enter the body; though it happens rarely they can cause secondary malignancy a decade or more later.) She also believes that proton therapy is extremely important to the future of cancer care. "These patients are already sick from cancer," she says, "Why make them get sicker from treatment? Now, we can make them more comfortable — killing cancer cells but not killing normal cells. Now, they can live a normal life while getting treatments." Whatever happens next in this field, Dr. Ritsuko Komaki and her colleagues at UT M. D Anderson are likely to be at the forefront.