Imaging Technology Group Report
Leading off the subsequent reports by the breakout groups, the imaging technology group focused on the evaluation of NIST’s Biochange 2008 Lung Cancer Assessment Metric. A point of agreement among the participants was the need for a greater number of cases with high-resolution images associated with reliable markup of lesion boundaries. The next concern was whether a group of radiologists or a new software tool should be considered as the gold standard for defining the lesion boundary. The group agreed that this was a dynamic issue for the foreseeable future. They also noted the need for a greater number of cases in which treatment response and other clinical outcome information is available. This triggered a complex discussion on how to define “ground truth” in regard to clinical outcomes—another topic for which the answer was heavily dependent on the specific trial context.
The imaging technology breakout group established three main recommendations. First, they agreed that continued evaluation of therapy assessment algorithms was important to sustaining progress in the field. The second recommendation focused on ensuring that open databases containing an abundance of thin-slice CT scans of lung cancers are assembled for algorithm development and evaluation. Finally, they emphasized the importance of obtaining fundamental acquisition characteristics for the assembled CT scans, such as the three-dimensional point spread function and noise properties. The deployment and use of the pocket calibration phantom developed by Cornell and NIST as well as the concept of embedding calibration phantoms into CT-scanning tables were discussed as potential solutions.
A number of speakers commented on the common lung imaging challenges shared by lung cancer and COPD. These tobacco-induced diseases share anatomy and disease pathogenesis, and COPD often arises in individuals afflicted with lung cancer. A research opportunity in this regard may be the reciprocal contribution of image processing across the drug development efforts for these two diseases and perhaps into cardiovascular disease. The challenge is to create support for this approach across academia, government, the advocacy community, and industry, to allow the critical cross-disciplinary conversations to proceed while redundant efforts are minimized and critical mass of stakeholders is ensured.
The clinical research breakout group discussed many technical issues surrounding optimization of imaging-driven trials. However, their key message was the essential need for effective cross-disciplinary teams. Accrual of patients to these studies occurred most readily in centers that had ongoing early-detection research efforts, where early-stage cancer patients were being routinely identified for surgical intervention. Close coordination of radiologists and the diagnostic workup team was critical to allowing the protocol proceed smoothly. Many trial design issues, especially in regard to optimal metrics (volume change, change analysis, or a variety of other endpoints) were discussed, with no clear winner evident at this early time. The approach suggested by Dr. Lee, using the Bayesian adaptive design, was deemed attractive for efficiently evaluating drug candidates in early lung cancer.
The most pressing challenge identified by the strategic breakout group was the perception that the potential of imaging tools in drug development is largely unrecognized by most clinicians, many in industry, and most importantly, the public. There is a need to disseminate information to potential stakeholders about the near-term benefits in a setting where modest research investments could have a great impact.
The meeting concluded with an appreciation of the contribution by NIST in making concrete steps to start the algorithm-development process. The completion and reporting of the first neoadjuvant, window-of-opportunity trial emerging from this Workshop series was the high point of the meeting. Participants recognized the great progress made with image processing in both the COPD and cardiovascular imaging communities, and the group was excited about greater interaction between investigators from these related areas of imaging research. Workshop attendees expressed continued frustration about the slow accrual of imaging cases, especially at high resolution. The Lung Cancer Alliance’s Give-A-Scan project and the Prevent Cancer Archive developed at Cornell were both appreciated as important efforts. Extending the window trial strategy to additional molecular targets is a key opportunity in efforts to improve the lung cancer drug development process.