ASTRO 2015

Can early stage NSCLC be treated with stereotactic radiation therapy?

Dr David Palma – London Health Sciences Centre, London, Canada

Could you comment on the session on using stereotactic radiation therapy in patients with early stage NSCLC?

Tomorrow at ASTRO we’re doing a session on stereotactic radiation for stage 1 lung cancer, so that’s lung cancer that has not spread anywhere else, where the standard treatment has been surgery and radiation has always been the second choice. With this new stereotactic radiation we are seeing outcomes that are just as good as surgery. So traditionally the radiation has only been used for patients who have not been candidates for surgery but now we’re talking about moving the radiation into new indications: for patients who might be candidates for surgery, for patients who have oligometastases like we’re talking about today, and also we’re talking about using radiation as a mechanism to turn on the immune system. There’s a hypothesis that when we give a big precise dose of radiation and we kill some of the cancer that’s there it can serve as a vaccine within the body. Now, that’s still experimental and there’s lots of work to do but there is lots of early data suggesting that we can turn on the immune system, either with the radiation alone or combining the radiation with some of the new immune therapy drugs, and that’s what we’re talking about tomorrow.

What other data are you discussing during the meeting?

We’re having a session on radiomics. Radiomics is a brand new field that’s only been around for 5-10 years. Basically what it is is it’s using imaging, using imaging in a new way. So let’s say a patient has a CT scan; normally we’d look at the scan, we’d look at the tumour, maybe we’d measure it, maybe we’d even outline it and calculate its volume, that would be the most we would do. But now there are new computer programs that can analyse that data in a new way. I say it’s more than meets the eye, to quote the old transformers logo, or the transformers theme. The computer can look at patterns within the tumour that we can see ourselves but they’re very hard to describe in human language but a computer can notice subtle differences, relationships between different intensities on the scan and that information can be quite useful. Early data suggests that radiomics can be helpful, it can correlate with a gene expression profile of the tumour and it looks like it can be a prognostic factor. So it’s being looked at as a way to determine which patients are going to do well and which ones are going to not do so well after radiation and also to see when you’re done your treatment did the treatment work or not. Radiomics is being investigated as a way to tell maybe three months after treatment did it work or do we have to do something else and if it worked then we can back off and just keep an eye on you but if it didn’t then we can do something different. So it’s a brand new field that has just opened up but it’s very exciting and it’s just made possible by all these advances in technology that have come from meetings like this over the years.

What is your take home message?

The final take home message, I would say, is that in radiation oncology what we see are clinical things come to fruition based on small steps over many, many years. We’re talking a lot about stereotactic radiation, it sounds very glamorous, we give doses that we couldn’t give before with precision that we couldn’t give before and when we talk to patients we say we have this exciting new technology. But we have to remember that that technology came about because of a large number of very small projects all put together, baby steps: all the physicists who developed the new treatment planning systems, all the companies that developed the new treatment delivery platforms, all the radiation oncologists who did small projects. So when I say to my trainees, residents and the physicists who are learning and doing this project, I say it might seem like a small step that you’re doing but when you take it in the context of everything else, when you bring it to meetings and share it with other people, then that’s how even the small things can make a big difference.