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John W. Mitchell, Senior Correspondent | March 13, 2018
Dr. Ashok Joseph Theruvath
From the March 2018 issue of HealthCare Business News magazine
A team of researchers has demonstrated that a single PET/MR imaging protocol is effective in assessing whether pediatric cancer patients have sustained harm to their brain, heart or bones from chemotherapy treatments.
HealthCare Business News checked in with Dr. Ashok Joseph Theruvath, postdoctoral research fellow in the Molecular Imaging Program at the Stanford School of Medicine and one of the researchers, to learn more about the protocol and its potential real-world applications.
HCB News: Why did you develop the protocol?
Dr. Ashok Joseph Theruvath: There has been a lot of focus on finding a cure for cancer and trying to treat patients with different cancer therapy regimens. Because of higher survival rates and better treatments, we see more pediatric cancer survivors.
But the downside of chemotherapy is there are going to be side effects, especially long-term damage to healthy organs. In adults who are 60 to 70 years old [organ damage] … is not going to show up 20 or 30 years later. But in kids who have developing organs, they have a high chance to develop secondary injuries due to the chemotherapy.
So, we wanted to develop a single imaging approach that can assess the most common chemotherapy injuries. Nowadays, there are separate imaging scans for the brain and the heart. But with PET/MR, we can image all these organs in one session.
HCB News: Have discoveries made from using the PET/MR protocol had any impact on the way you think about pediatric cancer treatment?
AJT: We look for injuries after chemotherapies. So, one might think the chemotherapy should be lowered. But it's a risk/benefit analysis. On the one hand, a lower dose to avoid long-term side effects could mean the patient doesn't get cured. I think the first step is the patient gets cured, and then we think about if the dose can be lowered to get the same result.
HCB News: How does earlier detection of chemotherapy-related injuries and abnormalities impact outcomes?
AJT: In the pilot of 10 patients, the results we got were pretty good. If we can confirm these results in a larger group, then I think it will definitely have a high impact on survival rates because we can detect injuries earlier.
Brain injury incidences after chemotherapy, for example, are in about half of the kids. Heart injuries also occur in about half of the kids, and bone injuries are in 10 to 20 percent of these patients.
There are studies where you can detect heart injuries early on, so you can give beta blockers to reduce the cardiotoxicity of chemotherapies. In some patients, the bone tissues can die. If we detect the injury soon enough, we can intervene with surgery. Once the patient has symptoms of bone injury, it's irreversible.
HCB News: What is the next step you plan to take to validate this PET/MR protocol? And what are the key challenges in advancing this research?
AJT: I think we need several hundred to a thousand patients. There are not high numbers of these patients, so I think we need multiple sites and even international study to come together and upload their imaging data. Each site could answer different questions around this issue.
The PET/MR is expensive and only large academic centers have it. But most pediatric cancers are treated in large academic centers, so I think it can be done. There are now drug sensitivity tests, so if you have a patient who gets a specific cancer therapy, you can test the patient towards the drug they should get. We discuss this in our paper. So, combining these drug sensitivity tests with our PET/MR scan could be ideal.
