Introduction to Neoplasia

In 2020, an estimated 10 million deaths world-wide were attributed to cancer. Cancer remains the second leading cause of mortality after heart disease and considering excess mortality due to the COVID pandemic. Of these deaths, cancers of the lung and airways made up approximately 25%. Cancers are genetic diseases caused by mutations and deletions of genes resulting from radiological, chemical, and viral agents. Genetic drivers of cancers include mutations and/or deletions in genes controlling cell growth and differentiation. Environmental factors such as lifestyle and diet are critically important in affecting the risk of developing cancer (see "Relevant Websites" section). Cigarette smoking is the single most impactful and avoidable risk factor, presenting highly potent, chronic exposure to carcinogens. Given the importance of accumulating driver mutation over time to the occurrence, cancer due to environmental causes is generally seen as a disease of old age. Given that contemporary therapies largely fall short of cures and often result in considerable morbidity, current research continues to address the causes, development, and treatment of cancers of virtually all tissues across the lifespan. During the past 10 years, great improvements are noted in the survival and quality of life following diagnosis and treatment of many types of cancer.