Oral Cancer Prevention

According to the World Health Organization, oral cancer is the 13th most common cancer on the planet.   The Centers of Disease Control and Prevention estimates that oral cancer will cause 54,000 new cases of oral cancer (2022).  If not detected early, these cancers are devastating and deadly.

I recently examined a patient with a white spot in their mouth which led me to review the current state of head and neck cancers (aka oral cancer).  What I found was so interesting that I am sharing it with you.  

The potential to prevent such cancers is large.  Studies are underway to determine the best prevention strategies but until they are completed, there are sensible, affordable and safe things you can do now.  But first, lets learn about it!

What is Oral Cancer?

Oral cancer is a catch-all term for Squamous Cell Carcinoma of the Head and Neck (SCCHN).  This type of cancer occurs in the lining of the mouth, throat and esophagus.  Tobacco use, alcohol intake and human papillomavirus (HPV) are all highly linked to cancers of this type.  There is something particularly unique about cancers is this part of the body called “field cancerization”.

What is Field Cancerization?

In most cancers elsewhere in the body, the cancer cells develop in one part of the body and create a swelling at that site, potentially spreading through the bloodstream or directly growing into nearby tissues. This type of spread is called metastasis. 

In SCCHN, the simple occurrence of a cancer in one area of the mouth or throat dramatically increases the chances of finding another, new, unrelated cancer in other areas of the head and neck, not through metastasis.  This strange proliferation of cancers in the head and neck is called ‘field cancerization’ and is only seen in this area of the body.  Fortunately, these cancers, like others, develop in definite stages (transformed, invasive, and metastatic).  This transformational process is called multi-step carcinogenesis.  This musti-step process opens the door to attacking these cancers at intermediate and earliest stages which can result in termination of the cancer growth before irreversible damage occurs..

Field Cancerization

In the simplest terms, field cancerization describes the frequent observation of head and neck cancers occurring in multiple areas and from multiple lineages. It’s as if the mucus membrane of the whole head and neck is somehow primed for cancer development.  The observed cancers are either recurring at the site of the original cancer, or appear somewhere else in the mouth, throat or esophagus.  These recurrences can occur soon or many months after the first cancer is found.  Genetic tests on these cancers show that most are not related to the original growth.  In addition, pre-cancer cells have been found in the lining of the mouth far from the site of the original growth.

In total, field cancerization means that trying to treat the first cancer site with surgery or other cancer-killing approaches will be futile since other sites of not-obvious cancer are already present.

Treatment Strategies for Head and Neck Cancers

Because of field cancerization, direct treatment of newly discovered head and neck cancers often fails.  Thus,  the goal of modern head and neck cancer is to change the cancer tendency of the mucus memberane cells throughout the head and neck. These strategies are:  1. Stopping exposure to carcinogens like tobacco, alcohol; 2. Chemoprevention that reverses or prevents continued transformation in cancer cells; and, 3. Screening of patients that are at high risk due to ongoing carcinogen risk or previously recognized pre-malignant areas.

Stop Exposures

Since carcinogens can trigger transformation of cells from normal to cancerous at any point, it makes sense to eliminate these risk factors as soon as possible.  Unfortunately, taking these risk factors away will not cause cancer cells to reverse their cancerous transformation. In addition, in the real world, stopping exposures to alchol and tobacco can be very difficult.  Cancer due to human papilloma virus (HPV) has dramatically increased in the past few years.  This is the type of throat cancer Michael Douglas is fighting.  Stopping exposure to this carcinogen is more complex and is being actively studied.  The good news is that there is now a vaccine, Gardisil 9 that eliminates the HPV virus by immunizing against it!  This vaccine was originally approved for females, ages 9-26 years but has since been FDA approved for both men and women, ages 9-45 years.

No matter which risk factor, reduction in carcinogen exposure is practically very difficult.  For that reason, additional intervention strategies are needed.

Screening

This strategy is based on identifying people at increased risk of getting cancer, either from carcinogen exposure or from previous head & neck cancer.  Hopefully, these cancers will be found in an early developmental stage. Once found, these patients are then encouraged to reduce carcinogen exposure, and consider chemoprevention.

Who gets screened?  Everybody!  But especially those with known risk factors like alcohol and tobacco use.

Does if work?  Many studies around the world have shown screening programs to be quite effective at improving survival in oral cancer patients. 

Chemoprevention

Theoretically, it is possible to reverse or slow cancer transformation in cells. Exposure to a variety of natural and synthetic chemicals has been shown to slow or reverse cancer transformation.  The use of these substances to slow or reverse cancer is called ‘chemoprevention’.

Chemoprevention can be used in patients with a previously diagnosed cancer or pre-cancer area in the mouth (such as those spotted by screening), or it can directed toward completely preventing such changes in patients who are at high risk (alcohol, tobacco).

The natural and synthetic chemicals used for chemoprevention have been found to be effective in a variety of models, including humans.  However, clinical studies using standard double blind, randomized control trial design – the design that we use in all of western medicine – have not been done.

So, in this setting, we are considering use of chemicals that are suspected of but not definitively proven to slow or reverse cancer transformation.  If the chemicals involved were associated with toxic side effects that make them more dangerous than potentially helpful, I wouldn’t continue this discussion beyond this point.  But, as you will see, incorporating chemoprevention strategies can be achieved without significant risk of injury.  In this setting, it makes sense to talk about them.

Chemicals for Cancer Prevention?

Measuring the effect of a chemical on cancer transformation requires long-term research studies.  As an alternative, scientists study the action of a chemical on the structure, genetics or chemistry of cancer cells and use their findings to extrapolate potential effects in humans.  In such studies, the influence of these chemicals is measured at the following levels:  1) cancer cell structure; 2) genetic alterations; 3) Cancer promotion proteins; 

Folate

Of all the chemicals studied, folate seems to have particularly intriguing chemoprevention potential.  For example, a deficiency of folate has been noticed in many patients with SCCHN.  At the cellular level, such a deficiency may disrupt the DNA of cells in a way that sets cancer transformation in motion.  Reversing the deficiency by adding folate to the diet has been associated with better outcomes in at least one study.  

There are particular folks who might be deficient in folate because of another health issue.  These issues are: pregnancy, chronic gastrointestinal disease, weight-loss diets, alcohol dependence, and age greater than 65.

How much to supplement?  The only clue comes from a study showing that intake of at least 320 mcg folate daily was associated with better survival after SSCHN was diagnosed. Supplemental folic acid tablets come in 400 mcg, 800 mcg and 1 mg so simply taking a 400 mcg tablet daily seems sensible.

Other Chemicals

Zinc and selenium are two trace metals have theoretical action on cellular growth but preliminary studies have not shown benefit in oral cancer. 

Clinical Trials

Vitamins A and E and Beta carotene:  These chemicals, found in nature in vegetables, have been studied for their ability to slow or reverse cancer transformation.

All of these agents appear to slow or reverse cancer cell transformation temporarily BUT, the cancer returns when they are stopped.  At the present time, none are recommended for either prevention of oral cancer  in high risk patients or reversal of cancer transformation in patients with identified cancer or precancer.

Wellivery tracks the research in this area and will update this section with new findings as they arrive.

Everyday Oral Cancer Prevention

Oral cancer is a complicated problem.  But, there are simple truths and simple actions we can take in an effort to prevent or control it.  Here’s what we know:

1. It is a big problem internationally.
2. Alcohol and tobacco are strong promoters.
3. HPV is a newly recognized promoter.
4. Folate seems preventative.

So,

1. Stop alcohol and tobacco use.
2. Have regular screening to find these cancers early;
3. Take daily folate supplementation.

We will have to wait for more research to guide our response to HPV oral cancer.

For now, If you notice a white area on the inside of your mouth, lips, or back of throat, or notice hoarseness, swallowing difficulty or a change in your voice, see your doctor for an exam.  And if you smoke, its time to stop!  Smoking Cessation for You!

Cancer prevention is a major goal for Wellivery!  Cancer is just one of the chronic disease problems we attack along with diabetes and heart disease.