Inside Cancer Therapy Response and Comparative Effectiveness
PET imaging can play an invaluable role in monitoring the effects of cancer therapies. In my view, cancer therapies that do not achieve early reductions in FDG uptake cannot be effective. Unfortunately, the imaging community has thus far failed to establish firm PET-based response criteria such as those proposed as PERCIST by Dr. Richard Wahl. Moreover, we need to provide solid data and standardized PET imaging criteria to increase the acceptance of this technology among oncologists.
Such solid data could arise from comparative effectiveness studies to prove the value of diagnostic imaging modalities, as discussed in another section of this issue. As it pertains to imaging, comparative effectiveness research is designed to provide evidence on effectiveness, benefits, and harms of different diagnostic options. The evidence is generated from research studies that compare various diagnostic tests and their role in addressing specific clinical problems. It has recently become clear that regulatory bodies have raised the required evidence level to arrive at coverage decisions. One example is the requirement for a multicenter clinical trial in addition to a recently established registry (NOPR) to provide evidence that bone imaging with 18F-sodium fluoride affects not only patient management but also patient outcome. While it would be valuable to establish such evidence, it also would be important to consider how outcomes should be defined. Obviously, patient survival is a critically important outcome marker. However, others such as cost and side effects of therapies that could be avoided by improved patient stratification are also very important considerations.
It also is important to keep the concept of comparative effectiveness studies in mind when we propose and promote PET imaging for assessing therapy responses or when we introduce new imaging technologies. In breast cancer, for instance, a variety of novel probes and technologies will be available in the near future. Our arsenal also includes a few new dedicated systems. Which patient populations will benefit from these technologies and how are we going to design studies to prove their value?
As physicians, we have always been concerned about the radiation doses our patients receive. While these discussions are frequently irrational in elderly cancer patients, they are very important and rational in our pediatric patients. We need to find ways to minimize radiation exposure further for these patients. This can be achieved by reducing the radiation from both the CT and the PET components of PET/CT. We will have to show, however, that these reductions do not result in poor, maybe even non-diagnostic, image quality. Some methods have been created, but more kid-focused solutions are needed.
Johannes Czernin, MD
Professor, Molecular & Medical Pharmacology
Director, Nuclear Medicine Clinic, Positron Emission Tomography/Computed Tomography
David Geffen School of Medicine at UCLA, Los Angeles, Calif.
Such solid data could arise from comparative effectiveness studies to prove the value of diagnostic imaging modalities, as discussed in another section of this issue. As it pertains to imaging, comparative effectiveness research is designed to provide evidence on effectiveness, benefits, and harms of different diagnostic options. The evidence is generated from research studies that compare various diagnostic tests and their role in addressing specific clinical problems. It has recently become clear that regulatory bodies have raised the required evidence level to arrive at coverage decisions. One example is the requirement for a multicenter clinical trial in addition to a recently established registry (NOPR) to provide evidence that bone imaging with 18F-sodium fluoride affects not only patient management but also patient outcome. While it would be valuable to establish such evidence, it also would be important to consider how outcomes should be defined. Obviously, patient survival is a critically important outcome marker. However, others such as cost and side effects of therapies that could be avoided by improved patient stratification are also very important considerations.
It also is important to keep the concept of comparative effectiveness studies in mind when we propose and promote PET imaging for assessing therapy responses or when we introduce new imaging technologies. In breast cancer, for instance, a variety of novel probes and technologies will be available in the near future. Our arsenal also includes a few new dedicated systems. Which patient populations will benefit from these technologies and how are we going to design studies to prove their value?
As physicians, we have always been concerned about the radiation doses our patients receive. While these discussions are frequently irrational in elderly cancer patients, they are very important and rational in our pediatric patients. We need to find ways to minimize radiation exposure further for these patients. This can be achieved by reducing the radiation from both the CT and the PET components of PET/CT. We will have to show, however, that these reductions do not result in poor, maybe even non-diagnostic, image quality. Some methods have been created, but more kid-focused solutions are needed.
Johannes Czernin, MD
Professor, Molecular & Medical Pharmacology
Director, Nuclear Medicine Clinic, Positron Emission Tomography/Computed Tomography
David Geffen School of Medicine at UCLA, Los Angeles, Calif.