This book presents in detail the problems and ethical challenges in daily oncological practice. In western industrialized countries, roughly 25 percent of all citizens still die from cancer. Despite significant progress in basic science and in individual areas of clinical care, even in the 21st century, being diagnosed with cancer has lost none of its dread and can still be a death sentence. This situation raises many problems and challenges for medical ethics, e.g., the question of the benefits and risks of prevention programs, or the right to know and not to know. Clinical trials with cancer patients and quality assurance for surgery, radiotherapy and medication also pose a series of ethical dilemmas. Furthermore, cancer treatment is a psychological challenge not only for patients but also for physicians and caregivers.