Cancer is a leading cause of mortality, and while new therapies have improved patient outcomes in some areas, there remain many cancers for which the prognosis is very poor. This is especially true for certain cancer that can remain undetected until it is too late for curative treatment. The World Health Organization estimates that 30-50 percent of cancers are preventable, making cancer prevention a priority for reducing cancer-related mortality.
This article will highlight the latest advancements in the field of cancer prevention, which provide new insights into lifestyle and environmental factors that can contribute to cancer onset.
Research efforts are constantly underway to understand new ways to reduce our cancer risk. History of smoking is a well-established risk factor for cancer, but other contributing risk factors are less clearly defined. Understanding new cancer risks and implementing preventative measures are essential for winning the global battle against this disease.
Diseases often run in families, and the same is true for many cancer types. Understanding the genetic basis of disease can help identify individuals at high risk of developing cancer, enabling them to take proactive measures to lower their risk.
Mutations in the genes BRCA1 and BRCA2 are well-known examples of cancer-associated mutations. Mutations in these genes increase an individual’s risk of developing breast, ovarian, and other cancers. Preventative measures in this context include bilateral mastectomy to remove breast tissue and more frequent screening to catch cancer when it is at an early and more treatable stage.
Personalized medicine allows preventative measures to be tailored to specific individuals based on their genetic profiling. We’ve already mentioned increased screening and mastectomy for patients with BRCA1 and BRCA2 mutations. Another example is the more frequent screening of individuals with Lynch Syndrome, a genetic condition that increases a person's risk of developing certain types of cancer, especially colorectal cancer, often at a younger age than usual. Preventive measures for Lynch Syndrome include increased surveillance and chemoprevention, which we will discuss later.
Genetic predisposition plays a significant role in many cancers. However, many people are not aware of their risk. Genetic counseling and testing are crucial for individuals with a family history of cancer, especially for cancer types with a known genetic component. This counseling can help individuals understand their risk and make informed decisions. For example, individuals with multiple first-degree relatives with cancer or many individuals with the same type of cancer may benefit from genetic testing.
Screening and early detection play an essential role in reducing cancer-associated mortality by allowing cancers to be detected at earlier, more treatable stages.
Advanced imaging technologies have improved our ability to detect cancer early. Furthermore, many imaging technologies provide healthcare providers with information such as cancer stage and subtype, which helps to direct appropriate patient care without the need for a biopsy. In pancreatic cancer, elastography is an emerging imaging technique that can measure tissue softness and identify more solid areas that can indicate the presence of cancer.
Digital Breast Tomosynthesis (DBT) is a type of 3D mammogram that takes multiple X-ray images of the breast from different angles, and it has been reported to increase cancer detection rates. Increased radiation exposure is a significant drawback of this technique.
Diagnosis often requires invasive procedures to obtain tumor biopsies. Furthermore, patients may be reluctant to undergo imaging-based screening. Liquid biopsies use markers found in bodily fluids like blood to help diagnose different cancer types. These biopsies provide less invasive ways to detect cancer and guide patient care. In pancreatic cancer, blood markers like circulating tumor DNA and circulating tumor cells are being increasingly used to detect this cancer type, which is typically asymptomatic at the early stages.
Healthcare providers are increasingly using artificial intelligence (AI) to aid cancer screening and risk assessment. One area where AI is particularly powerful is image analysis. New AI technologies allow faster and more accurate analysis of scan images to detect cancer. Deep learning reconstruction (DLR) helps to improve image quality and sharpness, which can be particularly important in situations where obtaining clear images is challenging. As AI continues to improve, it will likely play a more significant role in improving diagnostic accuracy.
Chemoprevention is the use of medications, vitamins, or supplements to inhibit, delay, or reverse the development of cancer before it becomes invasive. It aims to reduce cancer risk, especially in individuals who have a higher likelihood of developing cancer due to factors like family history, genetic predisposition, or personal health history.
Chemopreventive agents work through various mechanisms to reduce cancer risk:
Hormonal Agents: These target hormone-dependent cancers by interfering with hormone signaling. Selective estrogen receptor modulators (SERMs) like tamoxifen and raloxifene block estrogen receptors in breast tissues, reducing the risk of estrogen receptor-positive breast cancers.
Anti-Inflammatory Agents: Non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin have shown potential in reducing the risk of colorectal cancer and other cancers by suppressing inflammation.
Antioxidants: Some vitamins and natural compounds are thought to prevent DNA damage caused by free radicals, potentially reducing cancer risk. However, the evidence for their effectiveness is mixed.
Several chemopreventive agents have demonstrated effectiveness in clinical trials. Tamoxifen and raloxifene have been approved by the FDA for breast cancer prevention in high-risk women. Regular use of aspirin has been associated with a 20-40 percent reduction in the risk of developing colorectal polyps and cancer. However, long-term use and potential side effects need to be carefully considered. Aromatase inhibitors like anastrozole and exemestane have shown promise in reducing breast cancer incidence among postmenopausal women at increased risk.
From 1989 to 2021, an estimated 5 million cancer deaths were avoided. These figures are attributable in part to preventative eradication of Helicobacter pylori, which is a risk factor for gastric cancer, and hepatitis B vaccinations, which help prevent liver cancer. Furthermore, the HPV vaccine helps to prevent cancers of the throat, anus, penis, vagina, cervix, and vulva linked to HPV infection.
Research into new cancer-preventive vaccines is an active area of study. The success of mRNA technology in COVID-19 vaccines has sparked interest in mRNA-based cancer treatment vaccines.
Immunotherapy is also being explored for its potential in cancer prevention. This concept focuses on boosting the immune system’s ability to recognize and eliminate precancerous cells before they develop into established cancer.
Some preventive strategies focus on enhancing the overall function of the immune system to improve its cancer surveillance capabilities. Cytokine therapies are being explored to boost the activity of immune cells that play a role in identifying and destroying abnormal cells. Checkpoint inhibitors, which have shown success in cancer treatment, are being investigated for their potential in preventing cancer recurrence in high-risk individuals.
Recent research continues to strengthen the link between diet and cancer prevention, highlighting the importance of overall dietary patterns rather than individual foods or nutrients. For example, the Mediterranean diet, which is rich in fruits, vegetables, whole grains, legumes, nuts, and olive oil, has been linked to a reduced risk of several cancers. One study using UK Biobank data found that greater adherence to cancer prevention recommendations, which closely align with the Mediterranean diet, was associated with a 7 percent lower risk of all cancers for each one-point increase in adherence score.
Based on current research, the following dietary recommendations may help reduce cancer risk:
Numerous studies have demonstrated that higher levels of physical activity are associated with a reduced risk of cancer. One recent study found that the relationship often follows a dose-response pattern, where increased levels of physical activity correlate with greater reductions in cancer risk.
Engaging in leisure-time physical activity, such as walking, running, swimming, and racquet sports, for 7.5 to less than 15 metabolic equivalent hours per week has been associated with a 13 percent lower risk of cancer mortality. Higher-intensity activities such as running and competitive sports provide a slightly greater reduction. For example, they have been associated with a 27 percent reduction in breast cancer risk.
