Stereotactic ablative radiotherapy (SABR) has been found to be a viable curative-intent treatment option among some patients with early-stage non-small cell lung cancer (NSCLC) and lung scarring known as interstitial lung disease, according to research.
“Our radiation has improved, just like the phones that we use have improved since the ’80s, the technology changes have been on that massive scale,” Dr. David Palma, a clinician scientist at the Ontario Institute for Cancer Research in Canada, explained in an interview with CURE®. “In the old days, [when] we used to deliver radiation to lung cancer, we would zap [patients] with a beam straight through from the front and a beam straight through from the back. So two beams just blasting right through, we couldn’t see the tumor very well because the imaging wasn’t very good and we’d have to treat a big area of the lung because you didn’t know exactly where the tumor was.
“Now, when we deliver radiation, we can see a tumor as a patient is breathing, if it’s moving up and down, and we can target it when it’s right in the right spot within a design, very complicated radiation plans where the radiation is coming in from all these different angles. And what happens is you get the tumor very tightly enveloped in the high dose of radiation, so the side effects are a lot lower.”
Palma was among the researchers on a trial, the findings of which were published in JAMA Oncology, studying the use of SABR in 39 patients with interstitial lung disease and early-stage NSCLC.
Researchers found overall survival (the time a patient lives, regardless of disease status) to be 79% at one year, with a median overall survival of 25 months. The median progression-free survival (the time a patient lives without their disease spreading or worsening) was 19 months and the two-year local control (no progression of the primary cancer) rate was 92%.
Regarding side effects, 30.8% of patients (12 patients) experienced grade 1 to 2 (mild or moderate) side effects, 10.3% (four patients) experienced grade 3 (severe) side effects and three patients, or 7.7%, experienced fatal, or grade 5 side effects, due to respiratory deterioration.
These findings, researchers wrote, support “the use of SABR for curative-intent treatment after a careful discussion of risks and benefits. Further studies exploring pharmacologic options to reduce radiotherapy-induced toxic effects may be beneficial in this population.”
Palma spoke with CURE® about the study and its findings.
Transcript:
For patients who have lung cancer, some of these patients have an underlying lung condition that shows up as scarring of their lungs. This lung condition is called interstitial lung disease. So, it’s a chronic scarring that some patients have, and these patients who have this lung scarring tend to be more likely to get cancer. And this lung scarring, this interstitial lung disease, can be caused by a lot of things. It can be associated with autoimmune things like rheumatoid arthritis, it can be associated with exposures, like asbestos, or even to pets or birds. And we know that people who have this lung scarring if they have lung cancer, their risks of side effects are a lot higher. So if you have this lung scarring and they need to remove part of the lungs, your risk of a bad outcome is higher, because your lungs don’t work as well.
Same with radiation, and radiation is often used as a treatment for lung cancer to try to cure it. As a background, we have this very precise form of radiation that we use a lot for people with lung cancer to try to cure their lung cancer. And that radiation is called stereotactic radiation. And there’s been a bit of concern in the past about giving stereotactic radiation to these patients with this lung scarring, this interstitial lung disease, because the risk of side effects, in some reports, has been really, really high. And that’s because when you already have some lung scarring, and we give radiation on top of that, you can get more lung scarring and that can be a big problem. And that puts us into a bind.
Because … what happens as the patient is that you have a new lung cancer, which if you don’t treat is usually going to cause problems, it could be fatal. But if you treat it with radiation, then you have the potential of a very serious side effect. So, a few years ago, we designed this study. The idea was that if we give the radiation very carefully, with a lot of support from lung doctors [and] radiation doctors, to manage any side effects that come up, can we deliver this safely to try to give patients a chance to get their cancer treated? What we had said with this study is that we were hoping to show that by giving the radiation, the side effects would be lower than we had worried about and that patients on average would survive more than a year. Because the reason I put that year mark, is we know that if you don’t treat lung cancer, usually within a year, it can be fatal. So, we enrolled over 39 patients, and we delivered this radiation carefully. We had careful assessments by lung doctors called pulmonologists. And we found that the outcomes for patients were way better than we expected. And the average survival wasn’t a year — it was over two years. And although there were some patients with serious side effects, the rates of side effects were a lot lower than we expected.
Transcript has been edited for clarity and conciseness.
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