Doctors’ technique puts tumors on ice
WASHINGTON (AP) — Robin Imhof watched, fascinated, as her doctor stuck a needle into the dime-sized lump in her breast and pumped freezing gas through it. On a nearby ultrasound monitor, a round image gradually turned lighter and lighter — her noncancerous but extremely painful tumor being encased in a ball of ice.
It didn’t hurt — the cold itself was anesthetic even as it froze the growth to death. No hospital stay, stitches or scar. An hour later, the Ferndale, Wash., woman headed home to wait for the lump to shrink over the next few months, her body slowly absorbing the destroyed cells.
Doctors have long attacked tumors with heat. Now a few clinics around the country are turning to cold.
Called cryoablation, it’s being used to extend the lives of people dying from liver cancer, to treat prostate cancer, and as the first nonsurgical alternative for the half-million women who have benign breast tumors removed each year. Doctors have just begun testing it as a possible scar-free way to remove early breast cancer, and as an alternative to open surgery for kidney cancer.
It’s catching on slowly — the delicate technique requires special training to avoid serious side effects from accidentally freezing healthy tissue, and it has a controversial history.
But “it made perfect sense,” says Imhof, explaining why she chose cryoablation over standard breast surgery. “I thought, ‘Yeah, the simple science of stuff in your freezer decaying <#201> that makes really good sense.”‘
Cryoablation, which destroys cells by shattering their outer walls during freeze-and-thaw cycles, actually was first hailed in the 1960s. But it proved too risky for much deep-body use — doctors couldn’t see what they were aiming to freeze and thus had high complication rates. Dermatologists and gynecologists continued to freeze away easy-to-see skin or cervical growths, but other uses of cryoablation faded away.
Today it’s making a slow comeback thanks to improved medical imaging that allows doctors to see deep in the body while they work. They can place a needle that emits freezing gas — argon is used primarily — in a tumor or organ and literally watch until ice encases it.
“You could see it so exquisitely under ultrasound,” said Dr. Gary Onik, who pioneered cryoablation’s return.
The first approved use is in patients whose colorectal cancer had spread to the liver and become inoperable. Cryoablation offers the hope of buying them some time; Onik says about 20 percent of his patients survive five years.
For prostate cancer, cryoablation proved more difficult. Bad aim causes serious side effects in the bladder or rectum; inconsistent freezing can miss cancer. But after years of research — and bad publicity from what Onik says were poorly trained doctors and technology companies rushing the procedure — a recent study published in the journal Urology suggests a careful cryoablation technique may be as effective as a widely used treatment, radioactive seed implants.
Like other prostate treatments, however, cryoablation can cause impotence.
So Onik, at Florida Hospital/Celebration Health, is experimenting with a nerve-sparing version in hopes of reducing that risk.
On to the breast: Sanarus Medical Inc. recently won federal approval of its cryoablation system to destroy fibroadenomas, benign breast tumors like Imhof’s.
Now the company is conducting two pilot studies to test whether cryoablation might treat breast cancer, too. In one study, 25 women will have small cancers frozen. Three weeks later, they’ll undergo a lumpectomy — standard surgery — so scientists can examine the lump for any cancer cells left lurking around the edges. The hope is that cryoablation might someday replace lumpectomies for certain women.
In the second study, another 25 women will undergo cryo-assisted lumpectomy, as scientists test whether freezing tumors that are hard for surgeons to feel can help them remove all the cancer on the first try.
“There’s tempered enthusiasm,” said study investigator Dr. J. Stanley Smith of the Pennsylvania State College of Medicine, cautioning that it will take years to prove whether the technique works.
Other scientists are testing freezing for kidney cancer patients who are poor candidates for grueling open surgery.
Experiments aside, patients considering even approved uses of cryoablation should pick an experienced cryosurgeon, warns Dr. LaMar McGinnis of the American Cancer Society: It takes lots of training and practice to avoid complications.