News on Cryoablation

[Joan M]

Here is a news story from MedPage Today on using cryoablation for lung metastases. I wonder what would have happened if patients didn't have "few remaining treatment options," as the story noted.

In 2008, I had an RFA of the lung, which is also a minimally invasive, interventional radiology treatment. Cryoablation is freezing a tumor, while RFA is burning it.

IR procedures are an option for women with oligometastatic disease, or limited metastatic disease. They are also an alternative to surgery: they are minimally invasive and could be tried before surgery (however, a surgeon probably wouldn't agree with that).

Also, IR procedures are exactly like chemo in outcome: They work well for some survivors but not others.

I had a discussion yesterday with my onc while getting treatment. For women with oligometastatic disease, he first gives chemotherapy. If the patient's tumor(s) has shrinkage but not a complete response, he will then remove the tumor(s), because he realizes that he's not going to get more shrinkage with that drug. He said that he prefers to get out the tumor(s) on the upside. That is, when the patient is having a response, and not waiting until the downside when several lines of chemotherapy have failed and the situation is starting to get out of control. I like him because he's open, logical, and reasonable in his thinking. Why be dogmatic?

As to evidence based medicine based on clinical trial results, how do we know that that model fits in every situation. Often an onc will say that there's no evidence that a local procedure works. However anecdotal evidence (that's from a patient's perspective) and case studies (which is the same anectodal evidence, but from an onc's perspective) have shown that some patients do do well. Should we not use them just because up to now phase III clinical trials have not yet been conducted? But that is changing.

My onc recently treated a friend of mine with surgery for mets to the skin in the chest area. She had been treated at the same citadel in NYC that I was treated at for about a year, until I got hip and got out (even though I had my brain surgery and radiation there and managed to get the RFA of my lung there, as well). In general, the breast service there is very much against local procedures, even though I can't speak for each individual onc. My friend had been taking Herceptin and Xeloda, and even though her skin looked pretty good, a biopsy showed bc cells. The skin was removed with clear margins, and I'm praying for NED for her. My friend will be continuing on her treatment for a while and hopefully she will be able to eventually take only Herceptin.

Yes, I know that I go on and on about IR, but it's my bc soapbox. For others it could be supplements or something else. I think there's a natural tendency to want to push for what has worked pretty well for each of us.

Joan

Freezing Lung Metastases Helps, Early Trial Shows

By Todd Neale, Senior Staff Writer, MedPage Today

Published: April 15, 2013

Reviewed by F. Perry Wilson, MD, MSCE; Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

NEW ORLEANS -- CT-guided cryoablation of lung metastases may provide some benefit to patients with few remaining treatment options, a phase I study suggested.

In patients with small-to-medium metastases in one or both lungs, the minimally invasive procedure resulted in a 100% response rate -- no patients had worsening disease -- at 3 months and a 95% response rate at 6 months, according to David Woodrum, MD, PhD, of the Mayo Clinic in Rochester, Minn.

In addition, there was a low complication rate and most of the adverse events were minor, he reported at the Society of Interventional Radiology meeting here.

These "preliminary, short-term results offer promising local tumor control," Woodrum said.

Cryoablation "adds value to the patient in that we're able to treat patients who may not have been surgical candidates and we can treat them in a way that decreases their time necessary in the hospital," he said on a conference call in advance of the meeting.

He acknowledged, however, that larger and longer studies will be needed to evaluate the technique, and, in particular, whether the local tumor control has an effect on survival.

Woodrum reported preliminary results from the ECLIPSE study, a prospective, single-arm study conducted at three centers in the U.S. and one in France to assess the feasibility of using cryoablation for local tumor control in patients with pulmonary metastatic disease.

The study included 40 patients (mean age 63; 60% male) who had up to five lung metastases no bigger than 3.5 cm, and no more than three on one side. The study excluded patients with primary non-small cell lung cancer, those who couldn't lie flat or those with respiratory distress at rest, and those with uncontrolled coagulopathy or bleeding disorders.

The most common primary cancer diagnoses were colon cancer (40%) and kidney cancer (23%) and the average size of the metastases was 1.4 cm.

The patients were considered for the study because their disease was progressing despite the use of chemotherapy, according to Woodrum. Generally, chemotherapy was stopped for about 2 weeks before cryoablation and then restarted after the procedure.

Most patients (80%) had tumors in one lung only. The total number of cryoablation procedures was 48.

The procedure involved placement of cryoablation probes into the tumors using CT guidance, at which point freezing began. CT also ensured that the ice ball completely engulfed the tumor. The procedure lasted 1.5 hours on average.

The side effects that occurred were mostly minor, Woodrum said. The most common were pneumothorax (50%), pleural effusion (21%), pain in the chest or back (13%), hemorrhage (8%), and cough (6%).

There were only three grade 3 events, including one case each of noncardiac chest pain, pneumothorax requiring video-assisted thoracoscopic surgery, and arteriovenous fistula thrombosis requiring thrombectomy.

By 3 months, no patients had a local failure, 80% had stable disease, and the rest had a partial or complete response.

By 6 months, there was one local failure, with the rest of the patients having stable disease or a partial or complete response.

Only two patients have reached the 12-month follow-up so far, one with a complete response and one with a partial response.

Those results are promising, Woodrum said.

The study has a planned follow-up duration of 5 years, and other factors the researchers will be examining include overall and disease-specific survival, the time to disease recurrence or progression, and the patients' physical function and quality of life.

Before cryoablation for local control of pulmonary metastases gains acceptance in the clinic, Woodrum said, the complication rate would need to stay low and tumor control would need to remain good over the longer term.

Cryoablation of metastases is not a cure for the cancer, he said, noting that new metastases may pop up.

"But hopefully by treating the disease that we can see, we can prolong their fight with the cancer and prolong their good lifestyle," he said. "Hopefully we've made their quality of life better."