1. Sjoukje Lubberts, MD, Department of Medical Oncology, University Medical Center Groningen and University of Groningen, Groningen, the Netherlands; Flora E. van Leeuwen, PhD and Michael Schaapveld, PhD, Department of Epidemiology, Netherlands Cancer Institute, Amsterdam, the Netherlands; and Jourik A. Gietema, MD, PhD, Department of Medical Oncology, University Medical Center Groningen and University of Groningen, Groningen, the Netherlands