Major strides are being made in understanding cancer and potential molecular flaws that can be targeted in its treatment. Cancer is a disease in which molecular flaws lead to abnormal cell proliferation, lack of controlled growth, and the ability of malignant cells to invade and metastasize. Von Eschenbach, the former director of the National Cancer Institute, stated that understanding the abnormal signaling pathways in the cell and the process of metastasis is critical to reducing the many deaths from cancer and therein allowing patients to live with cancer as a “chronic disease.” With this focus in mind, cancer researchers continue to identify characteristics of the cancer process that may lead to therapeutic breakthroughs. For instance, we now know that solid tumors cannot grow beyond 1 to 2 mm, the diffusion distance of oxygen, without developing new blood vessels via the process of angiogenesis. The concept of limiting tumor growth so that metastases does not occur is a new one, in which the tumor will remain small, and cancer then becomes a “chronic illness.” This understanding has led to new anticancer agents, which target the different malignant flaws that cause tumors to grow, invade, and metastasize.
Nurses, who have provided the mainstay of care for patients receiving anticancer therapy, need to keep abreast of major developments in therapy, including targeted therapy. In many instances, nurses administer targeted therapies in the form of monoclonal antibodies such as trastuzumab (Herceptin), mTOR inhibitors (Torisel), or other targeted agents. In addition, they educate patients and families about what targeted therapy is, how it differs from chemotherapy, potential side effects, and self-care measures to help patients adhere and benefit from an often long course of oral therapy, as with erlotinib (Tarceva). Because the side effect profile of targeted therapy differs from that of chemotherapy, oncology nurses, defined as any nurse who cares for patients with cancer and their family, must understand the emerging pathophysiology of cancer, how these targeted agents work, their
side effect profile, and measures to help patients minimize toxicity and maximize adherence to therapy.
Of these learning needs, understanding the emerging pathophysiology of cancer may be the most challenging. There has never been a more exciting time for oncology nurses. As our understanding of cancer rapidly evolves, we are offered new targets and opportunities to stop cancer for those patients who do not achieve cure and to make cancer a truly chronic disease for these patients. Nurses, however, have often forgotten much of basic cell biology, or they had a minimal exposure to it during their basic nursing education. This book is designed to help nurses understand the newly emerging science of cancer against a backdrop of normal cell biology, in a nonfrightening manner.
Because this complex material is best understood when combined with relevant nursing implications, the chapters are organized according to the corresponding tumor biology, which underpins the mechanisms of action of the drugs administered in cancer treatment. The categorization of these agents is based on the work of Ma and Adjei. Chapter 1 provides a foundation for exploring cancer biology. It includes a discussion of inflammation and the microenvironment, together with the other six cardinal hallmarks of cancer. Chapter 2 offers an overview of monoclonal antibodies; membrane-bound receptors and their signaling pathways; the agents that target these pathways, intracellular signaling kinases (including Hedgehog) and their pathways; heat shock proteins; and the ubiquitin–proteasome pathway and inhibitors. Chapter 3 addresses angiogenesis, angiogenesis inhibitors, hypoxia-inducible factor, m-TOR inhibitors, and epigenetic abnormalities. It also discusses agents that influence methylation and histone conformation. Chapter 4 addresses the microenvironment from the perspective of bone metastasis and describes ways of targeting flaws in the processes of apoptosis and mitosis. Chapter 5 discusses some of the challenges in supporting patients on oral anticancer therapies, including managing drug interactions in the P450 microenzyme system and adhering to oral regimens. Each chapter includes a discussion of the pathophysiology, key drugs that target malignant flaws, and nursing implications.
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