that public health experts intensify efforts designed to improve the understanding and mitigation of these inequities. Only with new insights obtained through innovative and inclusive research, such as basic research using biospecimens from diverse populations, clinical studies involving participants from all sociodemographic backgrounds, and health care delivery research that is representative of everyone in the communities, will we be able to develop and implement interventions that eventually eliminate cancers for all populations. Variable Progress Against Different Types of Cancer and Stages of Diagnosis Among the current challenges in cancer science and medicine is the uneven progress against different cancer types and different stages of a given cancer type. These challenges are illustrated by the fact that the 5-year relative survival rates for U.S. patients vary widely depending on both the type of cancer diagnosed and the stage at diagnosis (5). For example, the overall 5-year relative survival rates of 94 percent for patients with melanoma and 97 percent for patients with prostate cancer stand in stark contrast to the overall 5-year relative survival rates of 23 percent for those with liver cancer and 13 percent for those with pancreatic cancer. In addition, among women with breast cancer and men with prostate cancer, those whose cancer is confined to the breast, or to the prostate, have 5-year relative survival rates of 99 percent and 100 percent, respectively, while those whose cancer has metastasized have 5-year relative survival rates of 31 percent and 34 percent, respectively (5). Variable progress among different cancer types can be partly attributed to the availability of novel cutting-edge therapeutic options, or lack thereof, that have moved rapidly from the laboratory to the clinic and are now available to patients. As one example, between January 1, 2011, and July 31, 2023, the U.S. Food and Drug Administration (FDA) approved five immunotherapeutics and six molecularly targeted therapeutics for use alone or in combination for the treatment of patients with metastatic melanoma, a previously intractable cancer. Thanks to these innovative new therapeutics, melanoma mortality rates have declined rapidly between 2011 and 2020 by about five percent per year in adults younger than age 50 and three percent per year in those 50 and older (28). In contrast, progress has been slow for patients with glioblastoma multiforme (GBM), an aggressive form of brain tumor (see Tackling Difficult-to-Treat Cancers, p. 147). Since the approval of the chemotherapeutic temozolomide nearly 25 years ago, no new anticancer agents have shown promise in improving overall survival. Consequently, the 5-year relative survival rate for patients with GBM remains at a dismal seven percent (29). Developing new and effective methods for early detection of more cancer types could help address the challenge of variable progress between types of cancer because the likelihood of cure is much higher when cancer is diagnosed at an early stage while it is confined to its original location than when it has spread to distant sites. Additionally, intensive research into the molecular underpinnings of cancer initiation and progression is vital in order to improve future therapeutic options for currently hard-to-treat diseases (see Tackling Difficult-to-Treat Cancers, p. 147). The Growing Population Burden of Cancer The public health challenges posed by cancer are predicted to grow considerably in the coming decades unless we develop and implement more effective strategies for cancer prevention, early detection, and treatment (30). In the United States alone, the number of new cancer cases diagnosed each year is expected to reach nearly 2.3 million by 2040 (30). This is because cancer is primarily a disease of aging; 57 percent of diagnoses occur among those 65 and older (28), and this segment of the U.S. population is expected to grow from 54.1 million in 2019 to nearly 81 million in 2040 (31). Also contributing to the projected increase in the number of U.S. cancer cases are the high rates of obesity and physical inactivity and the continued use of cigarettes by 11.5 percent of adults (32). However, it should be noted that a significant proportion of lung cancers (16 percent in women and 10 percent in men) are diagnosed in individuals without a history of smoking (33) and there is a need for more research to determine whether the incidence rate of lung cancer among those without a history of smoking is increasing (34). Identification of risk factors, characterization of disease, and development of evidence-based early detection and treatments are critical needs to lower the burden of lung cancer in the population of patients who do not have a history of smoking. While overall cancer incidence in the United States has stabilized in recent years, the incidence of certain cancer types such as pancreatic cancer and uterine cancer (5) is steadily increasing. Additionally, many recent studies have reported an increase in the incidence of colorectal cancer among individuals younger than 50 years, a phenomenon referred to as early-onset cancer (35,36). According to a recent report, between 2011 and 2019, the colorectal cancer incidence rate increased by 1.9 percent per year in people younger than 50 years (35). Many of the early-onset colorectal cancer cases are diagnosed at an advanced stage. Between 2010 and 2019, among 20- to 49-yearold individuals, incidence of advanced-stage colorectal cancer increased by about three percent per year (35). Understanding the reasons behind rising cases of early-onset colorectal cancer is an area of intensive research. To reduce AACR Cancer Progress Report 2023 Cancer in 2023 20
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