A Northern Medical Program doctor is part of a study showing high-dose radiation therapy substantially improves survival in patients once thought to be incurable.
Dr. Robert Olson is included in the international research team who put together the first randomized phase two clinical trial of its kind. Olson explained the results of the trial, treating oligometastatic patients with a form of high-precision cancer therapy called stereotactic ablative radiotherapy (SABR).
“We’ve doubled the progression-free survival from six months to 12 months, and we’ve also shown a doubling in the number of people that are alive at five years,” explains Olson.
“Almost half of the patients, even though they have metastatic cancer, on the experimental arm are alive at five years, which is a pretty amazing finding.
“The conventional wisdom is that when a patient has cancer that has spread (also known as metastasized) to other parts of their body such as lung, brain, or bone, they were considered to be incurable, and radiation was reserved to alleviate symptoms.”
Each of the 99 patients had been treated for cancer but it had returned, with tumours appearing in as many as five different places. All patients had good performance status and a life expectancy of more than six months.
The first patient accrued in BC is from Prince George. Similar treatment has been seen in the northern capital already.
“We use it for curative lung cancer when you can’t have surgery. When it’s being used investigationally like this, it’s only available on trial,” says Olson, adding there could be other opportunities in PG as well.
“We actually have another trial, that is going right now, that isn’t randomized just to look for the side effects. Then we’ll be opening up for phase three and it will be available for Prince George on the trial.”
Phase three trials are different than phase two as it compares the newly tested treatment to the standard treatment, seeing if it is better, as good, or worse, and contrasts the side effects to the other. Olson will be leading the follow-up trial titled SABR-COMET-3, which will include patients with one to three sites of spread. This trial should be ready to open in spring of summer next year and will initially open in BC before expanding to international sites.
There are potential risks to the more aggressive treatment, Olson pointed out. He says stereotactic radiation resulted in more negative side effects than standard treatments.
“Stereotactic radiation therapy needs to be delivered carefully and by an experienced team, and there is a small risk of very serious side effects, as well as mortality. I believe that SABR should continue to be delivered in the setting of clinical trials. The primary purpose of this phase II trial is to provide evidence to proceed to a larger randomized phase III trial, which will ultimately provide definitive evidence for the use of SABR in the metastatic setting.”
The findings are being presented at the 60th Annual Meeting of the American Society for Radiation Oncology this week.
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