Annual Review of Medicine - Volume 72, 2021

Cancer immunotherapy has revolutionized the way that we think about treating cancer. Although checkpoint blockade therapy, including anti-PD-1/PD-L1 and anti-CTLA-4, has shown remarkable success, the responses are limited to only a subset of patients. This discrepancy highlights the many overlapping avenues for immune evasion or suppression that can be employed by a tumor. One such mechanism of immunosuppression is adenosinergic signaling within the tumor microenvironment. We provide an overview of the current status of clinical trials targeting the adenosine pathway, including CD73, CD39, and adenosine receptors. Additionally, we highlight several avenues that may be explored to further potentiate responses in the clinic by combining adenosine-targeting agents to target multiple arms of the pathway or by using conventional immunotherapy agents.

Aberrations in rat sarcoma (RAS) viral oncogene are the most prevalent and best-known genetic alterations identified in human cancers. Indeed, RAS drives tumorigenesis as one of the downstream effectors of EGFR activation, regulating cellular switches and functions and triggering intracellular signaling cascades such as the MAPK and PI3K pathways. Of the three RAS isoforms expressed in human cells, all of which were linked to tumorigenesis more than three decades ago, KRAS is the most frequently mutated. In particular, point mutations in KRAS codon 12 are present in up to 80% of KRAS-mutant malignancies. Unfortunately, there are no approved KRAS-targeted agents, despite decades of research and development. Recently, a revolutionary strategy to use covalent allosteric inhibitors that target a shallow pocket on the KRAS surface has provided new impetus for renewed drug development efforts, specifically against KRAS^G12C. These inhibitors, such as AMG 510 and MRTX849, show promise in early-phase studies. Nevertheless, combination strategies that target resistance mechanisms have become vital in the war against KRAS-mutant tumors.

Adoptive transfer of T cells modified with chimeric antigen receptors (CAR-T cells) has changed the therapeutic landscape of hematological malignancies, particularly for acute lymphoblastic leukemia and large B cell lymphoma, where two different CAR-T products are now considered standard of care. Furthermore, intense research efforts are under way to expand the clinical application of CAR-T cell therapy for the benefit of patients suffering from other types of cancers. Nevertheless, CAR-T cell treatment is associated with toxicities such as cytokine release syndrome, which can range in severity from mild flu-like symptoms to life-threatening vasodilatory shock, and a neurological syndrome termed ICANS (immune effector cell–associated neurotoxicity syndrome), which can also range in severity from a temporary cognitive deficit lasting only a few hours to lethal cerebral edema. In this review, we provide an in-depth discussion of different types of CAR-T cell–associated toxicities, including an overview of clinical presentation and grading, pathophysiology, and treatment options. We also address future perspectives and opportunities, with a special focus on hematological malignancies.

Preventable differences in colorectal cancer (CRC) mortality across racial/ethnic, economic, geographic, and other groups can be eliminated by assuring equitable access and quality across the care continuum, but few interventions have been demonstrated to do so. Multicomponent strategies designed with a health equity framework may be effective. A health equity framework takes into account social determinants of health, multilevel influences (policy, community, delivery, and individual levels), screening processes, and community engagement. Effective strategies for increasing screening uptake include patient navigation and other interventions for structural barriers, reminders and clinical decision support, and data to continuously track metrics and guide targets for improvement. Community resource gaps should be addressed to assure high-quality services irrespective of racial/ethnic and socioeconomic status. One model combinespopulation-based proactive outreach screening with screening delivery at in-person or virtual points of contact, as well as community engagement. Patient- and provider-based behavioral interventions may be considered for increasing screening demand and delivery. Providing a choice of screening tests is recommended for CRC screening, and access to colonoscopy is required for completion of the CRC screening process.

Patient-specific biomarkers form the foundation of precision medicine strategies. To realize the promise of precision medicine in patients with colorectal cancer (CRC), access to cost-effective, convenient, and safe assays is critical. Improvements in diagnostic technology have enabled ultrasensitive and specific assays to identify cell-free DNA (cfDNA) from a routine blood draw. Clinicians are already employing these minimally invasive assays to identify drivers of therapeutic resistance and measure genomic heterogeneity, particularly when tumor tissue is difficult to access or serial sampling is necessary. As cfDNA diagnostic technology continues to improve, more innovative applications are anticipated. In this review, we focus on four clinical applications for cfDNA analysis in the management of CRC: detecting minimal residual disease, monitoring treatment response in the metastatic setting, identifying drivers of treatment sensitivity and resistance, and guiding therapeutic strategies to overcome resistance.

High-quality evidence indicates that regular use of aspirin is effective in reducing the risk for precancerous colorectal neoplasia and colorectal cancer (CRC). This has led to US and international guidelines recommending aspirin for the primary prevention of CRC in specific populations. In this review, we summarize key questions that require addressing prior to broader adoption of aspirin-based chemoprevention, review recent evidence related to the benefits and harms of aspirin use among specific populations, and offer a rationale for precision prevention approaches. We specifically consider the mechanistic implications of evidence showing differences in aspirin's effects according to age, the potential role of modifiable mechanistic biomarkers for personalizing prevention, and emerging evidence that the gut microbiota may offer novel aspirin-associated preventive targets to reduce high-risk neoplasia.

Although numerous trials have convincingly shown benefits of statin therapy in both primary and secondary prevention of atherosclerotic cardiovascular disease (ASCVD), most showed relative risk reductions of 25–40%, and thus many individuals continue to have ASCVD events despite statin therapy. Substantial progress has been made in developing therapies that address the residual risk for ASCVD despite statin therapy. In this review, we summarize progress of currently available therapies along with therapies under development that further reduce low-density lipoprotein cholesterol and apolipoprotein B–containing lipoproteins, reduce lipoprotein(a), reduce ASCVD events in patients with high triglycerides, and directly target inflammation to reduce ASCVD risk.

Statins, ezetimibe, and PCSK9 inhibitors are currently the standard of care for the prevention and treatment of coronary artery disease. Despite their widespread use, coronary artery disease remains the leading cause of death worldwide, a fact that pleads for the development of new protective therapies. In no small part due to advances in the field of human genetics, many new therapies targeting various lipid traits or inflammation have recently received approval from regulatory agencies such as the US Food and Drug Administration or fared favorably in clinical trials. This wave of new therapies promises to transform the care of patients at risk for life-threatening coronary events.

There is a growing interest in using wearable devices to improve cardiovascular risk factors and care. This review evaluates how wearable devices are used for cardiovascular disease monitoring and risk reduction. Wearables have been evaluated for detecting arrhythmias (e.g., atrial fibrillation) as well as monitoring physical activity, sleep, and blood pressure. Thus far, most interventions for risk reduction have focused on increasing physical activity. Interventions have been more successful if the use of wearable devices is combined with an engagement strategy such as incorporating principles from behavioral economics to integrate social or financial incentives. As the technology continues to evolve, wearable devices could be an important part of remote-monitoring interventions but are more likely to be effective at improving cardiovascular care if integrated into programs that use an effective behavior change strategy.

More than a century after its synthesis, daily aspirin, given at a low dose, is a milestone treatment for the secondary prevention of cardiovascular disease (CVD). Its role in primary prevention of CVD is still debated. Older randomized controlled trials showed that aspirin reduced the low incidence of myocardial infarction but correspondingly increased the low incidence of serious gastrointestinal bleeds without altering mortality. More recent trials see the benefit attenuated, perhaps obscured by other cardioprotective practices, while the bleeding risk remains, especially in older patients. Indirect evidence, both preclinical and clinical, suggests that aspirin may protect against sporadic colorectal cancer and perhaps other cancers. However, further studies are still necessary to warrant the consumption of aspirin for primary prevention of CVD and cancer by apparently healthy individuals.