Cancer occurs when our cells grow and reproduce uncontrollably, causing the formation of a tumour. This is a lump of cells which can invade healthy tissues. Cancer can develop in any part of the body, and cells can even spread to other body parts, a process known as metastasis. Head and neck cancers can be found in the mouth, nose, sinuses, and the salivary glands in your throat. The most common type from this group is mouth cancer, such as the lips or tongue.1
Ninety per cent of head and neck cancers are squamous cell carcinomas, known as head and neck squamous cell carcinoma (HNSSC), meaning they begin in squamous cells (flat, thin cells that look like fish scales). They act as a protective barrier, helping shield underlying tissues from infection, lining the head and neck surfaces. Nonsquamous cell carcinomas are very rare, and while more research is necessary, treatment requires input from across different specialities.1,2
Symptoms of head and neck cancer can vary depending on the exact location, but some general signs to look out for are:3
If you experience any of these symptoms, seek medical advice from a professional. The cancer must be caught early to give you the best chance at successful treatment.3
Risk factors are things that increase your chances of developing cancer. There are several key risk factors associated with head and neck cancers, including tobacco use, alcohol, infection, low immunity, and poor oral health. Understanding these risk factors is important to minimise your risk of developing cancer.1,3
The use of tobacco has been associated with many cancers, particularly lung cancer. However, it is also associated with bladder, pancreatic, and head and neck cancers, as well as other diseases, such as respiratory diseases. Tobacco products include traditional smoking tobacco like cigarettes and pipes, but also include smokeless tobacco, such as chewing tobacco and snus. Tobacco contains over 70 carcinogens (substances that can cause cancer), found through extensive research. One way in which these substances can lead to the development of cancer is through their binding to our DNA.4
DNA is the material in our cells carrying instructions that our cells need to survive and reproduce. When these substances bind, they can disrupt our DNA and cause mutations, potentially affecting its ability to give instructions to our cells. If these mutations occur in oncogenes, which are normally involved in regulating the division of cells, it may result in the gene being permanently switched on, allowing cells to divide uncontrolled, promoting cancer development. On the other hand, if a change/alteration occurs in a tumour suppressor gene, which usually manages cell growth by preventing progression of the cell cycle or promoting cell death, it may result in the gene no longer functioning, once again allowing out-of-control growth.4
Research has shown that patients with HNSCC who continue smoking while undergoing treatment have significantly worse outcomes, including a lower rate of 5-year survival. Furthermore, tobacco use affects wound healing, impacting outcomes after surgery, which can be a treatment option for HNSCC. Following treatment, continued smokers tend to have longer hospital stays and more complications, such as confusion and urinary tract infections.4
This shows that not only is smoking associated with the development of cancer, but it also has a significant impact on survival and treatment outcomes. Stopping smoking is a key measure in reducing your risk of cancer, but even if you are diagnosed with HNSCC, stopping can greatly improve your health and chances of survival.
Alcohol has been associated with HNSCC development in a dose-dependent manner, which means the more alcohol you drink, the higher your risk. Alcohol is a solvent, which increases how susceptible mucosal tissues are to carcinogens. These are the tissues where squamous cells are found. Acetaldehyde, produced from the ethanol in alcohol, is responsible for symptoms of drinking, such as headaches and is mutagenic, causing these mutations (alterations) in the DNA, which can potentially lead to cancer development.5
Alcohol consumption and tobacco use together have been shown in some studies to increase the risk of HNSCC 40-fold. Therefore, reducing alcohol intake and tobacco use are two significant ways to reduce the risk of HNSCC development. Both of these risk factors have been implicated in several cancers and other diseases, so the benefits of reducing or even stopping one or both would be significant.5
Human Papillomavirus (HPV) can cause cervical cancer, and research previously focused on this. However, recently, there has been an increasing number of other cancers being associated with HPV, including head and neck cancers, particularly with pharynx cancers.1,5
The DNA of the virus integrates itself into our DNA, and it contains genes called E6 and E7. These genes interact with our genes to promote cancer development. For example, E6 interacts with p53, a tumour suppressor, causing it to be broken down. This can allow cells to grow out of control, causing cancer development. There are a number of our genes that E6 and E7 can interact with similarly.5
The best preventative measure against HPV-positive HNSCC is vaccination. Now, the HPV vaccine is offered to both girls and boys of school age, and it offers protection against many of the HPV types which are considered high risk for cancer development. These vaccines not only protect you from head and neck cancer, they also prevent you from cervical, vaginal, penile, and any other HPV-associated cancers.5
There is some evidence of genetic susceptibility to HNSCC development. It is proposed that there are genetic factors which make you more susceptible to other risk factors, for example, inherited factors from relatives that make you more susceptible to the carcinogens in alcohol or tobacco.6
Everyone who smokes or drinks alcohol will develop HNSCC, suggesting that another factor might be involved. There are also some diseases you can inherit from parents, such as Fanconi anaemia (a rare genetic blood disorder), which compromises your ability to repair DNA when it becomes damaged. Fanconi anaemia is estimated to increase the risk of HNSCC by 500-700 times. In this specific case, the average age of cancer onset is 33, and most patients have never smoked or drunk alcohol.6
Poor oral hygiene is a risk factor in HNSCC. Studies have shown that those who brushed their teeth at least once a day were less affected by HNSCC. One suggested reason for this is that a build-up of bacteria in the mouth might make a favourable environment for cancer development; bacterial dysregulation and Candida albicans, a fungus, can produce acetaldehyde, which has been identified as a carcinogen in animals.7
Protective factors include:
While risk factors include:
The biggest risk is when these risk factors occur alongside others, such as smoking or drinking alcohol.7
Consumption of fruits and vegetables has been associated with lower cancer risk, including a lower risk of mouth cancer. This is because they contain minerals, such as folate and compounds such as resveratrol. These compounds have antioxidant and antitumour effects, which can promote a strong immune system. Furthermore, they can influence DNA repair and the regulation of the cell cycle.8
In patients with oral squamous cell carcinoma (OSCC), fruits and vegetables were consumed less frequently than dairy, red meat, and fried foods. Red meat can contain carcinogens, particularly when prepared in certain ways. Foods high in fat can also be carcinogenic. Research is still limited and often conflicting, for example, vitamin D found in dairy products can have anti-cancer effects, but their high fat content can be detrimental, so more research is needed, but a healthy diet containing plenty of plant products is likely to reduce your risk of cancer, as well as other diseases.8
There are several risk factors in the development of head and neck cancers. The main risk factors are smoking and alcohol consumption; however, several other significant factors may be involved. This includes poor oral hygiene, a poor diet lacking in fruits and vegetables, and high in red and salty meats; Viral infections, and genetic factors, as well as factors we have not touched on here, such as immune system deficiencies. It is most likely that a combination of factors is involved, acting together to lead to the development of cancer.
Many ways to prevent head and neck cancers will also prevent other cancers and diseases, as well as improve overall health, so the prevention benefits are huge. This involves stopping smoking and reducing alcohol consumption, eating a healthy diet and maintaining good oral hygiene. While prevention is the ideal situation when it comes to cancer, early detection and treatment improve outcomes. It is never too late to take steps towards improving your health.
