Imaging Tumor Response to Therapy

M. Aglietta and D. Regge, Eds.

New York, NY: Springer, 2012, 174 pages, $139

Cancer is a major human health problem, and a completely effective therapy is not available for most types of cancer. The expected benefit of the treatment is assessed in terms of a reduction in both the size of the tumor and dissemination of the cancer. Imaging is an ideal tool with which to evaluate response. The aim of using imaging as a surrogate biomarker for therapeutic response in oncology is to obtain a measure of disease extent and to better understand tumor response earlier than is possible with other biomarkers or with primary endpoints. When targeted therapy is available and can stabilize the disease, patient survival or quality of life improves to a greater extent than is possible with the transient tumor shrinkage induced by chemotherapy. There is evidence that tumor growth is strongly inhibited even if conventional imaging shows no change in tumor volume or a paradoxic increase. Therefore, in clinical practice the decision of whether to consider a treatment effective may be challenging. These problems are amplified during drug development, and improved patient survival is inappropriate in early clinical trials. Thus, surrogate endpoints of activity have become crucial. This book addresses these problems, and the detailed discussion of specific clinical situations contributes to and enhances the ongoing debate although it is not solved.

This relatively small book is organized into 3 parts with 9 chapters. Part I begins with the methodologic bases and discusses surrogate endpoints of clinical benefit and response to treatment, along with the role of imaging. Part II deals with the assessment of therapeutic response in metastatic disease from gastrointestinal stromal tumors, kidney cancer, and colon cancer. Part III covers the assessment of therapeutic response in locally advanced breast, lung, pancreas, and liver cancer. The book’s multidisciplinary perspective well addresses the assessment of therapeutic response. Finding more reliable and reproducible measures of tumor response is one of the most important and difficult challenges facing modern radiology, as it requires an entirely new approach to imaging. The figures are clear and helpful, and the references are current. There is no index.

Considering that no increase is expected in the number of new therapies with strong evidence of a survival benefit entering the market, and that demands for health-care cost containment are becoming increasingly pressing, the role of nonvalidated surrogate endpoints should be carefully reconsidered, both in practice and in research. The choice of the primary endpoint should be based on sound biologic, pathophysiologic, and statistical evaluations to produce the best outcome for patients, as well as to determine validity, sensitivity to the study treatment, and feasibility. In the development of evidence-based practice guidelines, the quality of the available evidence should be carefully assessed, with greater attention placed on the outcomes considered in the specific recommendations. I highly recommend this book to radiologists, nuclear physicians, oncologists, and imaging scientists.

• © 2013 by the Society of Nuclear Medicine and Molecular Imaging, Inc.