A Victoria-based clinical trial to begin this year will use artificial intelligence to better target the prostate gland so as to reduce cancer radiation therapy to two sessions from five, decreasing side effects and wait times.
B.C. Cancer Victoria radiation oncologist Dr. Abe Alexander is co-leading the clinical trial with Dr. Winkle Kwan in Surrey.
It’s called ADAPT-25 and stands for Artificial Intelligence-Driven Adaptive Prostate Stereotactic Radiation Therapy. It could help some of the 25,000 people diagnosed with prostate cancer in Canada each year — about 5,000 of whom die from the disease.
“We strive for 100 per cent cure rate [and] zero per cent side effects delivered in ideally one visit and I know we can never achieve that goal, but with our studies, we’re trying to get as close to that goal as possible,” said Alexander.
There are various treatment options for prostate cancer, with external-beam radiation being one of the more popular for eligible patients, he said. In the past, standard treatment included 20 to 40 treatments, with 28 being the previous standard in Victoria.
“There is good reason for us to believe that … giving two large treatments may be more effective for cancer control and may actually be associated with less side effects than when giving these more protracted courses,” he said.
In 2017, the first part of the clinical trial, called ASSERT, saw half of the 80 patients given five fractions of stereotactic ablative radiotherapy (SABR) — a more advanced technology with higher-intensity doses rather than the standard 28.
“Because they’re focused more accurately and precisely, we can give a smaller number of treatments but make each treatment bigger,” said Alexander.
The Victoria-based trial found patients tolerated the treatments well, had the same or fewer side effects and better quality of life, less travel and expense getting to appointments in Victoria, with less burden on wait times.
A similar British clinical trial showed 95 per cent of patients had the disease under control after five years.
“Computer technology has just skyrocketed, imaging technologies have skyrocketed, so now we’re able to plan these treatments with a level of precision and accuracy that was just never possible before,” said Alexander. “And we’re able to do much more complex things.”
Since the first clinical trial in Victoria, about 400 to 500 people over the last two years have undergone the new five-fraction radiation treatment and it’s becoming a standard approach in Greater Victoria, Surrey and other larger centres in B.C., he said.
Because of the success of the previous trial, the goal is to move forward with a new trial, said Alexander. “In order to get visits down to two from five, we need to take things to the next level in terms of precision and so we want to use an AI algorithm.”
The ADAPT-25 clinical trial is set to begin at the end of this year and will include 100 patients who have never had surgery or radiation as the primary treatment for their cancer. Researchers will compare the benefits or challenges of five fractions versus just two.
In the past, clinicians had no good way of dealing with slight patient movements during radiation treatments, but now, with advanced imaging, they can track the motion of the prostate in real-time while treatment is being delivered and make adjustments — increasing its efficacy and minimizing exposure for healthy tissues.
In the ADAPT-25 clinical trial, radiation therapists or technicians will use an artificial intelligence algorithm to run simultaneously during radiation treatment to target cancer cells, as opposed to the technician or radiation therapist manually targeting beams based on the most recent scan results.
“Artificial intelligence can analyze those images in ways that a human being cannot and can make dose calculations instantaneously based on what’s being seen that day, and then can suggest changes to adapt the treatment each day to make it more effective,” said Alexander.
There are several trials across Canada, the United States and other parts of the world on SABR treatments, “but to my knowledge at least there’s no head-to-head comparison of a five-treatment regimen versus a two-treatment regimen,” he said. “It’s the first, as far as I know.”
(A clinical trial called SIMPLIFY available at all B.C. Cancer centres will look at metastatic patients and assess the use of a single fraction of SABR in terms of toxicity, survival and quality of life.)
The $500,000 Victoria-based clinical trial is largely run on donor support through the B.C. Cancer Foundation.
Alexander said the trial has benefits for both patients and wait times.
Last year, the provincial government offered eligible prostate and breast-cancer patients who were waiting for radiation therapy the option of fully paid treatment at one of two cancer-care clinics in Bellingham, Washington to ease wait times in B.C. and ensure treatment occurred within the benchmark of 28 days.
B.C. Health Minister Adrian Dix said this week that about 500 patients have travelled to Bellingham under the program. “Space has been full every week since September.”
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