Radiation as a scalpel: Technique spares healthy tissue, treats inoperable tumors
FARGO — Meredith Staker's life depended in part on the accuracy of a face mask that vaguely resembles the type worn by hockey goalies. It had to be sculpted to the contours of her face in order to immobilize her head.
She would have to lie perfectly still while a machine delivered multiple beams of radiation that would converge in the back of her brain, in the location that enables her to see, with great precision.
The bursts of radiation were intense — much more intense than standard radiation treatments — but can be delivered with a degree of accuracy that spares the surrounding healthy tissue.
She would have to lie as still as a corpse. To help her do that, she was outfitted with a tailor-made mask, a sheet of heated plastic that would assume the shape of her face, and would be paired with another plastic sheet at the back of her head, forming a locking "sandwich" to prevent her head from moving, even slightly.
"I kind of pretended I was having a hot-wax spa treatment," she said later.
Staker was given a mild sedative to help her relax. Soothing music played in the background as the machine made multiple passes overhead, working its magic with a hum that she tried to think of as reassuring.
"I probably dozed," she said.
The single session, which would last 20 to 25 minutes, would be her best hope of eliminating the small tumor lurking deep inside her brain, the latest cancer threat facing the 61-year-old Fargo woman.
Her battle began seven years ago, when she was diagnosed with breast cancer, treated with surgery, chemotherapy and radiation. All was well until several years later, when a chest X-ray revealed that she had lung cancer.
Her lung cancer was treated with chemo and radiation. But life dealt her another wallop when a recent scan found the brain tumor. The lung tumor appears unrelated to her breast cancer, but her brain tumor had spread from her lung.
Rather than risk brain surgery — her tumor was inoperable — her first line of treatment at Sanford's Roger Maris Cancer Center was a technique called stereotactic body radiation therapy, sometimes called stereotactic radiosurgery.
The stereo reference involves matching images mapping the tumor with the pinpoint delivery of the beams of radiation — a marriage of sophisticated scanning and radiation enabled by advanced computing power.
The pinpoint radiation technique, which also is available at Essentia Health in Fargo, is suitable for small tumors, often in places that are inoperable, including the brain, lungs, liver, kidneys, prostate and spine.
Because healthy tissue is spared, side effects are minimal or nonexistent. Patients typically receive from one to five treatments.
"My skin never got red," Staker said. "I would not have known that I had any radiation." Better yet, her oncologists consider her brain and lung cancer cured. "I do feel blessed."
'Like Microsoft Paint'
Extensive imaging studies and planning are required before administering the radiosurgery. The radiation oncologist collaborates with a team that includes a medical physicist, dosimetrist and nurses.
"By the time we actually do it, it's easy," said Dr. Miran Blanchard, the radiation oncologist who treated Meredith Staker.
Before the radiation treatments, Blanchard uses a computer mouse to trace the area on a scanned image that will receive the radiation. "Just like Microsoft Paint," he said, referring to the computer painting program.
"You can really sculpt the radiation to funny, oblong shapes," he said.
The machine delivering the radiation travels along six arcs, rotating, twisting and twirling, delivering an "infinite number of beamlets as it travels along its arc," he said. "Each of these contains an insignificant dose, but when they all meet in the center it delivers a significant dose."
Treatments involving the lungs or abdomen are more complex, sometimes requiring hours of preparation, because the patient's subtle movements, including breathing, must be taken into account. They are captured in a "movie" of images that are then fed into the machine that delivers the radiation, so the radiation beams move in synchrony, sparing healthy tissue.
The four-dimensional scans required for pinpoint radiosurgery have been available for six or seven years, and, as techniques and equipment improve, applications for the procedure expand.
But the pinpoint radiosurgery has limitations. It doesn't work for cancers in bone or blood, or in tubular organs, such as the esophagus or intestines, or for large tumors.
Not long ago, many brain cancer patients had treatments that subjected the entire brain to radiation, causing side effects including cognitive deficits, including memory loss.
Now, with pinpoint radiosurgery, only the cancer is radiated, and most patients have no side effects. Blanchard compares the precision to "picking weeds" instead of "spraying the whole lawn with weed killer."
For three of every four patients treated with the technique, the expected outcome is to cure the cancer, Blanchard said, "or at least buy them tremendous amounts of time."
Now, for instance, half of patients with the most advanced form of lung cancer are eligible.
"Even a year ago, a curative attempt wouldn't have been made," Blanchard said. For those who aren't cured, "The vast majority have improvements in their quality of life."
Russell Koenig knew something was wrong when he woke up one morning with swollen legs. His doctor ordered blood work and promptly got on the phone with a kidney specialist, whom he saw the same day.
"My kidneys were shutting down on me," Koenig said. "It got worse and worse."
At one point, his kidney function was only 17 percent of normal — bad enough to qualify for a transplant, requiring five months of dialysis. The problem originated nearby in his pelvic region, where scans found cancer that had spread to a lymph node.
As with Meredith Staker, Koenig was treated with radiosurgery, as well as chemotherapy. Along the way, because of his weakened immune system, he developed a severe intestinal infection. But now he has rebounded, and there is no sign of cancer recurrence. As with Staker, he goes in every three months for screening scans.
His cancer involved small, scattered tumors, all bombarded with pinpoint radiation, delivered in five treatments.
"I feel fantastic," he said.
He is thankful for his recovery — but he and Staker must live with uncertainty and the gnawing possibility their metastatic cancer will return. Both view their lives differently as a result of confronting their cancer, and its rude reminders of human frailty and mortality.
"The little things are just little," said Koenig, a 59-year-old warehouse worker who lives in West Fargo. Now Koenig, who once routinely worked two jobs, and 65 hours a week, works part time. He and his wife recently traveled to Europe, a trip of a lifetime. He finds comfort in his faith.
"I've learned life is short. If you can do it, spend some time with your family and friends."
Staker's outlook is similar. "I can honestly say this journey has changed me completely," she said. "I've come to a place of surrender. If He calls me home, that's OK. I feel healthy right now."
Both try to get regular exercise and to avoid stress. Both are looking forward to spending time with family over the holidays.
"We just assume this is going to give me some more years," Staker said of her treatments. "How many, I don't know. It's up to the Lord.
"Right now, I'm just enjoying my life," she added. "It's a gift. I honestly feel like I can do whatever I want right now."