Head and Neck Cancer and Lipid Levels: New Horizons in Pathophysiology and Treatments

Head and neck cancers (HNCs) encompass a variety of sites including paranasal sinuses, nasal cavity, pharynx, nasopharynx, oropharynx, hypopharynx, oral cavity, tongue, salivary glands, larynx, and lymph nodes in the upper parts of the neck. HNCs are a heterogeneous group of highly aggressive tumors, and complete remission cannot be achieved in more than 50% of newly diagnosed cases. Although early-stage cases (stage I–II) generally have a favorable prognosis following surgery and radiotherapy, two thirds of advanced-stage (stage III–IV) cases display poor prognosis. Despite improved chemoradiotherapy and innovative surgery, the 5-year survival rate in HNC patients has not been significantly improved. Early identification of risk factors is crucial in reducing the morbidity and mortality of HNC. HNCs present with multifaceted risk factors from smoking to socioeconomic status. Cardiovascular disease (CVD) and HNC share common risk factors such as alcohol consumption, smoking, some viral infections and genetic changes. HNC risk is also associated with obesity, high cholesterol levels, and metabolic syndrome. Novel therapies utilizing the therapeutic targets in the cholesterol cycle have changed the clinical practice substantially. Lipids are responsible for maintaining cell integrity and are the regulators of cellular senescence in normal and malignant cells. The changes in lipid profile in HNCs are a subject of recent research. HNC patients suffer from cachexia, malnutrition, and suppressed immunity. For this reason, determining lipid levels in the early stages of cancer becomes important. The association between cancer and cholesterol has been a controversial debate. On one hand, shared mechanisms of dyslipidemia, atherosclerosis, metabolic syndrome, and insulin resistance stimulate carcinogenesis by causing inflammation. In advanced cancer, cholesterol levels tend to decline, and at that stage, low levels of cholesterol are associated with poor prognosis. Therefore, depending on the stage of cancer whether in the early or terminal stages, or depending on the pathophysiology of the individual cancer whether it is dependent on hormones or metabolic parameters such as breast cancer, the relationship between carcinogenesis and cholesterol changes. In near future, with the escalation of genetic susceptibility studies uncovering alterations in lipid metabolism, our comprehension of how this metabolism impacts HNC will improve. Modifying lipid levels favorably can be a future therapeutic target in HNC.