'After tobacco, the next most common cause for oral cancer is alcohol.
Is there a connection is between oral health and risk to cancer?
There is.
Not just cancer, oral hygiene is closely associated with several health problems, including cardiovascular disease, diabetes, adverse pregnancy outcomes and Alzheimer's disease.
This is what the article published in The Lancet Regional Health - Southeast Asia by oncologists Dr Abhishek Shankar and Dr Vaibhav Sahni from the All India Institute of Medical Sciences, New Delhi.
Dr Abhishek Shankar explains the direct link between oral health and the risk of cancer.
"Routine dental visits for 10 years are associated with reduced cancer mortality," Dr Abhishek Shankar tells Rediff's Shobha Warrier.
As an oncologist, when did you notice the link between cancer and oral health?
We have seen that people with bad oral hygiene and bad oral health have more propensity to develop infection. The outcome of it is bad.
Bad oral health is an important reason for the causation of cancer. Not just that, it is also important for the prognosis.
That was what made us look into the International Head and Neck Cancer Epidemiology (INHANCE) consortium, which had reported an analysis of 13 studies involving 12,527 controls and 8,925 HNC cases.
The result of these studies said that good oral hygiene defined by annual dental visits, fewer missing teeth and daily tooth brushing was associated with a moderate decrease in the risk of head and neck cancer. (Head and neck area consists of oral cavity, oropharynx area, nasopharynx area, hypopharynx area and larynx. Except the brain and the neck.)
The presence of the pathogenic oral bacteria such as porphyromonas gingivalis and prevotella intermedia has been shown to increase the incidence of cancer.
It was also reported that these bacteria adversely affect the overall outcome of cancer related mortality.
Our study has demonstrated through the Lancet commentary that oral health is very crucial not in terms of the incidence of cancer but in cancer therapy also.
How is cancer therapy connected to oral health?
Radiotherapy is one of the most important therapies for cancer related diseases in any area connected to the head and neck.
And when you give radiotherapy, it significantly alters the oral microbiome, which is reducing the beneficial bacteria and increasing potentially harmful species.
The oral microbiome which is present in our mouth is very beneficial but when radiotherapy destroys the microbiome, it leads to most post radiotherapy complications.
We have found that patients with severe periodontal disease have shown higher susceptibility to post-treatment bone healing complications when they undergo intensity-modulated radiotherapy (IMRT), with or without chemotherapy.
So, it is very important to note that bad oral health is not just a risk factor.
In fact, during the treatment, we always tell our cancer patients, especially older cancer patients, to take care of their oral health.
We always provide mouth wash etc to make sure that oral hygiene is maintained.
It is our customary practice that every cancer patient who is planned for radiotherapy must go for an oro-dental profile test.
We start radiotherapy only after treating any dental problem they suffer from.
Also, data from the CHANCE study revealed that routine dental visits for 10 years were associated with reduced cancer mortality.
Your study says that oral hygiene is implicated in cancer risk and its prediction, particularly in head and neck cancers. Can you please elaborate the prediction part?
If you have bad oral health, the chances of you getting oral cancer is high in comparison to those with good oral hygiene.
Any infection in the mouth for a longer period can lead to oral cancer.
You also say that poor oral health is closely associated with several health problems, including cardiovascular disease, diabetes, adverse pregnancy outcomes and Alzheimer's disease. In what way are oral health and Alzheimer's connected?
Infection in any part of the body is a very bad thing. It will have an adverse outcome in the related areas.
If you have bad oral health, it must be due to some infection. And if it is long standing, it will lead to many systemic diseases.
Being a cancer specialist, I am largely concerned about cancer and its outcome.
It is always pointed out that tobacco is the most dangerous as far as oral cancer is concerned. Other than tobacco, what are the other reasons that lead to oral cancer? These days, they say that sugary snacks and beverages are as bad...
Yes, tobacco is the most common cause for oral cancer. But these days, many people try to divert the attention from tobacco by talking about other things.
After tobacco, the next most common cause for oral cancer is alcohol.
People always consider alcohol as a risk factor for liver diseases. It is true.
But alcohol causes seven kinds of cancers. Alcohol causes oral cancer, pharyngeal cancer, cancer of larynx, etc. It is a very big area.
Another thing that needs to be highlighted is the multiplicative interaction.
For example, if you are taking tobacco and not taking alcohol, the chances of you getting oral cancer is 5 times.
If you are taking alcohol and not taking tobacco, it is 2 times and if you are taking alcohol and tobacco, it is 25 times.
This is what we call multiplicative interaction.
Added to this is air pollution. PM 2.5 is associated with many cancers.
We have advocated that we must extend warning level from tobacco and alcohol.
I say that it should not be restricted to 'Tobacco causes cancer, alcohol causes cancer'.
You need to work on the positive strategy too.
For example, it should be like, if you are an alcoholic and consuming alcohol for the last 5 years, kindly go for screening.
If you are consuming alcohol and also smoking, your risk increases by 25 times. So, please go for lung cancer screening.
Do you think people all over the world generally do not give much importance to oral hygiene?
In India, yes.
In the Eurasian region also, oral hygiene is not so good.
But when you go to the UK, it is better.
In the US, people smoke but you don't see them use tobacco.
You can understand how people value oral hygiene from the way dentists are respected in a country!
Where does India stand as far as oral hygiene is concerned?
There is a lack of awareness in every area here, and oral hygiene is one such area.
Oral hygiene is not a priority in India.
For behavioural changes, it takes time. If you start something today, it will take another 20 years to achieve a behavioural change.
Remember we have 260 million tobacco users in our country. If you brush your teeth and have tobacco the whole day, it is not going to help you.
In the backdrop of your study about the connection between oral health and cancer, what will be your advice to people?
Oral hygiene is very important as it is a risk factor for many diseases.
So, please take care of your oral health in whatever way possible.
Maintaining oral hygiene will be the best investment against disease occurrence and afterwards also.
It is the best preventive method to save your life from many diseases and the consequent suffering.
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Feature Presentation: Rajesh Alva/Rediff